TRINAMIC TMC260C-PA Datasheet

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POWER DRIVER FOR STEPPER MOTORS INTEGRATED CIRCUITS

TRINAMIC Motion Control GmbH & Co. KG Hamburg, Germany

TMC260C & TMC261C DATASHEET

BLOCK DIAGRAM

FEATURES AND BENEFITS

Drive Capability up to 2A motor current

Highest Voltage up to 60V DC (TMC261) or 40V DC (TMC260)

Highest Resolution up to 256 microsteps per full step

Compact Size 10x10mm QFP-44 package

Low Power Dissipation low RDSON & sync. rectification

EMI-optimized programmable slope, no charge pump

Protection & Diagnostics short to GND, overtemperature &

undervoltage, overcurrent and short to VS (-C types only)

StallGuard2™ high precision sensorless motor load detection

CoolStep™ load dependent current control saves up to 75%

MicroPlyer™ 256 microstep smoothness with 1/16 step input.

SpreadCycle™ high-precision chopper for best current sine

wave form and zero crossing

Improved Silent Motor operation (-C types only)

Stand Alone option (-C types only)

APPLICATIONS

Textile, Sewing Machines Factory Automation Lab Automation Liquid Handling Medical Office Automation Printer and Scanner CCTV, Security ATM, Cash recycler POS Pumps and Valves Heliostat Controller CNC Machines

DESCRIPTION

The TMC260 and TMC261 drivers for twophase stepper motors offer an industryleading feature set, including highresolution microstepping, sensorless mechanical load measurement, load-adaptive power optimization, and low-resonance chopper operation. Standard SPI™ and STEP/DIR interfaces simplify communication. Integrated power MOSFETs handle motor currents up to 2A per coil. Integrated protection and diagnostic features support robust and reliable operation. High integration, high energy efficiency and small form factor enable miniaturized designs with low external component count for cost-effective and highly competitive solutions. The new -C types TMC260C & TMC261C improve motor silence and add low side short protection and a stand-alone mode.

Highly efficient stepper drivers for two-phase motors with state-of-the-art features. Compatible

upgrade to TMC260A and TMC261A. Up to 2 A motor coil current. Step/Dir Interface and SPI.

TMC260C and TMC261C DATASHEET (Rev. 1.01 / 2020-AUG-11) 2

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Layout for Evaluation

APPLICATION EXAMPLES: SMALL SIZE – BEST PERFORMANCE

The TMC260 and the TMC261 score with power density, integrated power MOSFETs, and a versatility that covers a wide spectrum of applications and motor sizes, all while keeping costs down. Extensive support at the chips, board, and software levels enables rapid design cycles and fast time-to-market with competitive products. High energy efficiency from TRINAMIC’s CoolStep technology delivers further cost savings in related systems such as power supplies and cooling.

Layout for up to six stepper motors

ORDER CODES

Order code

Description

Size

TMC260C-PA

00-0183

CoolStep™ driver, up to 40V DC, TQFP-44

10 x 10 mm

TMC261C-PA

00-0184

CoolStep™ driver, up to 60V DC, TQFP-44

10 x 10 mm

TMC260C-PA-T

00-0183-T

-T devices are packaged in tape on reel

TMC261C-PA-T

00-0184-T

-T devices are packaged in tape on reel

TMC429+26x-EVAL

40-0030

Chipset evaluation board for TMC429, TMC260, TMC261, TMC262, and TMC424.

16 x 10 cm

*) The Term TMC260 and TMC261 is used for TMC260A / TMC261A or TMC260C / TMC261C within this datasheet. Differences in the C-types are explicitly marked with “C-type”. See summary in section 15. Non-C-type information is only given for reference.

TMCM-6110

FOR UP TO 6 STEPPER MOTORS

The TMCM-6110 is a compact stepper motor controller / driver standalone board. It supports up to 6 bipolar stepper motors with up to 1.1A RMS coil current. The TMC260 has been tested successfully for 2A peak (1,4A RMS) on this module.

The TMCM-6110 features an embedded microcontroller with USB, CAN and RS485 interfaces for communication.

All cooling requirements are satisfied by

passive convection cooling.

TMC429+TMC26X EVAL EVALUATION & DEVELOPMENT PLATFORM

This evaluation board is a development platform for applications based on the TMC260, TMC261, and TMC262.

Supply voltages are 8… 40V DC (TMC260) and 8… 60V DC (TMC261 and TMC262).

The board features an embedded microcontroller with USB and RS232 interfaces for communication. The control software provides a user-friendly GUI for setting control parameters and visualizing the dynamic responses of the motors.

Motor movements can be controlled through the step/direction interface using inputs from an external source or signals generated by the TMC429 motion controller acting as a step generator.

TMC260C and TMC261C DATASHEET (Rev. 1.01 / 2020-AUG-11) 3

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TABLE OF CONTENTS

1 PRINCIPLES OF OPERATION ......................... 4

1.1 KEY CONCEPTS ............................................... 4

1.2 CONTROL INTERFACES .................................... 5

1.3 MECHANICAL LOAD SENSING ......................... 5

1.4 CURRENT CONTROL ........................................ 5

2 PIN ASSIGNMENTS .......................................... 6

2.1 PACKAGE OUTLINE ......................................... 6

2.2 SIGNAL DESCRIPTIONS .................................. 6

3 INTERNAL ARCHITECTURE ............................. 8

4 STANDALONE OPERATION ............................ 9

5 STALLGUARD2 LOAD MEASUREMENT ....... 10

5.1 TUNING THE STALLGUARD2 THRESHOLD ...... 11

5.2 STALLGUARD2 MEASUREMENT FREQUENCY

AND FILTERING ............................................ 12

5.3 DETECTING A MOTOR STALL ........................ 12

5.4 LIMITS OF STALLGUARD2 OPERATION ......... 12

6 COOLSTEP LOAD-ADAPTIVE CURRENT

CONTROL ........................................................... 13

6.1 TUNING COOLSTEP ...................................... 15

7 SPI INTERFACE................................................ 16

7.1 BUS SIGNALS............................................... 16

7.2 BUS TIMING ................................................ 16

7.3 BUS ARCHITECTURE ..................................... 17

7.4 REGISTER WRITE COMMANDS ...................... 18

7.5 DRIVER CONTROL REGISTER (DRVCTRL) .... 20

7.6 CHOPPER CONTROL REGISTER (CHOPCONF) ..

................................................................... 22

7.7 COOLSTEP CONTROL REGISTER (SMARTEN) ...

................................................................... 23

7.8 STALLGUARD2 CONTROL REGISTER

(SGCSCONF) ............................................. 24

7.9 DRIVER CONTROL REGISTER (DRVCONF) ... 25

7.10 READ RESPONSE .......................................... 26

7.11 DEVICE INITIALIZATION ............................... 27

8 STEP/DIR INTERFACE .................................... 28

8.1 TIMING ........................................................ 28

8.2 MICROSTEP TABLE ....................................... 29

8.3 CHANGING RESOLUTION .............................. 30

8.4 MICROPLYER STEP INTERPOLATOR ............... 30

8.5 STANDSTILL CURRENT REDUCTION ................ 31

9 CURRENT SETTING ......................................... 32

9.1 SENSE RESISTORS ........................................ 33

10 CHOPPER OPERATION ................................... 34

10.1 SPREADCYCLE CHOPPER ............................... 35

10.2 CONSTANT OFF-TIME MODE ........................ 38

11 POWER MOSFET STAGE ................................ 40

11.1 BREAK-BEFORE-MAKE LOGIC ........................ 40

11.2 ENN INPUT ................................................. 40

12 DIAGNOSTICS AND PROTECTION ............ 41

12.1 SHORT PROTECTION..................................... 41

12.2 OPEN-LOAD DETECTION .............................. 42

12.3 TEMPERATURE SENSORS ............................... 43

12.4 UNDERVOLTAGE DETECTION ......................... 43

13 POWER SUPPLY SEQUENCING ................... 45

14 SYSTEM CLOCK ................................................ 45

14.1 FREQUENCY SELECTION ................................ 46

15 COMPATIBILITY TO NON-C-TYPE .............. 47

16 LAYOUT CONSIDERATIONS ........................ 48

16.1 SENSE RESISTORS ........................................ 48

16.2 POWER MOSFET OUTPUTS ......................... 48

16.3 POWER SUPPLY PINS .................................. 48

16.4 POWER FILTERING ....................................... 48

16.5 LAYOUT EXAMPLE ........................................ 49

17 ABSOLUTE MAXIMUM RATINGS ................ 50

18 ELECTRICAL CHARACTERISTICS ................ 51

18.1 OPERATIONAL RANGE .................................. 51

18.2 DC AND AC SPECIFICATIONS ...................... 51

18.3 THERMAL CHARACTERISTICS ........................ 54

19 PACKAGE MECHANICAL DATA ................... 55

19.1 DIMENSIONAL DRAWINGS ........................... 55

19.2 PACKAGE CODE ........................................... 55

20 DISCLAIMER .................................................... 56

21 ESD SENSITIVE DEVICE ............................... 56

22 TABLE OF FIGURES ........................................ 57

23 REVISION HISTORY ...................................... 57

24 REFERENCES ..................................................... 57

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1 Principles of Operation

µC

SPI

S/D

High-Level

Interface

0A+

0A-

0B+

TMC260 TMC261

0B-

µC

SPI

S/D

TMC429

Motion

Controller

for up to 3 Motors

High-Level

Interface

0A+

0A-

0B+

TMC260 TMC261

0B-

Figure 1.1 applications block diagram

The TMC260 and the TMC261 motor driver chips with included MOSFETs are intelligence and power between a motion controller and the two phase stepper motor as shown in Figure 1.1. Following power-up, an embedded microcontroller initializes the driver by sending commands over an SPI bus to write control parameters and mode bits in the TMC260/TMC261. The microcontroller may implement the motion-control function as shown in the upper part of the figure, or it may send commands to a dedicated motion controller chip such as TRINAMIC’s TMC429 as shown in the lower part.

The motion controller can control the motor position by sending pulses on the STEP signal while indicating the direction on the DIR signal. The TMC260/TMC261 has a microstep counter and sine table to convert these signals into the coil currents which control the position of the motor. If the microcontroller implements the motion-control function, it can write values for the coil currents directly to the TMC260/261 over the SPI interface, in which case the STEP/DIR interface may be disabled. This mode of operation requires software to track the motor position and reference a sine table to calculate the coil currents.

To optimize power consumption and heat dissipation, software may also adjust CoolStep and StallGuard2 parameters in real-time, for example to implement different tradeoffs between speed and power consumption in different modes of operation.

The motion control function is a hard real-time task which may be a burden to implement reliably alongside other tasks on the embedded microcontroller. By offloading the motion-control function to the TMC429, up to three motors can be operated reliably with very little demand for service from the microcontroller. Software only needs to send target positions, and the TMC429 generates precisely timed step pulses. Software retains full control over both the TMC260/TMC261 and TMC429 through the SPI bus.

1.1 Key Concepts

The TMC260 and TMC261 motor drivers implement several advanced features which are exclusive to TRINAMIC products. These features contribute toward greater precision, greater energy efficiency, higher reliability, smoother motion, and cooler operation in many stepper motor applications.

StallGuard2™ High-precision load measurement using the back EMF on the coils

CoolStep™ Load-adaptive current control which reduces energy consumption by as much as

75%

spreadCycle™ High-precision chopper algorithm available as an alternative to the traditional

constant off-time algorithm

MicroPlyer™ Microstep interpolator for obtaining increased smoothness of microstepping over a

STEP/DIR interface

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In addition to these performance enhancements, TRINAMIC motor drivers also offer safeguards to detect and protect against shorted outputs, open-circuit output, overtemperature, and undervoltage conditions for enhancing safety and recovery from equipment malfunctions.

1.2 Control Interfaces

There are two control interfaces from the motion controller to the motor driver: the SPI serial interface and the STEP/DIR interface. The SPI interface is used to write control information to the chip and read back status information. This interface must be used to initialize parameters and modes necessary to enable driving the motor. This interface may also be used for directly setting the currents flowing through the motor coils, as an alternative to stepping the motor using the STEP and DIR signals, so the motor can be controlled through the SPI interface alone.

The STEP/DIR interface is a traditional motor control interface available for adapting existing designs to use TRINAMIC motor drivers. Using only the SPI interface requires slightly more CPU overhead to look up the sine tables and send out new current values for the coils.

1.2.1 SPI Interface

The SPI interface is a bit-serial interface synchronous to a bus clock. For every bit sent from the bus master to the bus slave, another bit is sent simultaneously from the slave to the master. Communication between an SPI master and the TMC260 or TMC261 slave always consists of sending one 20-bit command word and receiving one 20-bit status word.

The SPI command rate typically corresponds to the microstep rate at low velocities. At high velocities, the rate may be limited by CPU bandwidth to 10-100 thousand commands per second, so the application may need to change to fullstep resolution.

1.2.2 STEP/DIR Interface

The STEP/DIR interface is enabled by default. Active edges on the STEP input can be rising edges or both rising and falling edges, as controlled by another mode bit (DEDGE). Using both edges cuts the toggle rate of the STEP signal in half, which is useful for communication over slow interfaces such as optically isolated interfaces.

On each active edge, the state sampled from the DIR input determines whether to step forward or back. Each step can be a fullstep or a microstep, in which there are 2, 4, 8, 16, 32, 64, 128, or 256 microsteps per fullstep. During microstepping, a step impulse with a low state on DIR increases the microstep counter and a high decreases the counter by an amount controlled by the microstep resolution. An internal table translates the counter value into the sine and cosine values which control the motor current for microstepping.

1.3 Mechanical Load Sensing

The TMC260 and TMC261 provide StallGuard2 high-resolution load measurement for determining the mechanical load on the motor by measuring the back EMF. In addition to detecting when a motor stalls, this feature can be used for homing to a mechanical stop without a limit switch or proximity detector. The CoolStep power-saving mechanism uses StallGuard2 to reduce the motor current to the minimum motor current required to meet the actual load placed on the motor.

1.4 Current Control

Current into the motor coils is controlled using a cycle-by-cycle chopper mode. Two chopper modes are available: a traditional constant off-time mode and the new spreadCycle mode. spreadCycle mode offers smoother operation and greater power efficiency over a wide range of speed and load.

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2 Pin Assignments

2.1 Package Outline

TMC260C-PA / TMC261C-PA

QFP44

OB1

OB2

BRB

VSB

DIR

GND

TST_MODE

STEP

GND

VHS

VCC_IO

SG_TST

TST_ANA / ST_ALONE

OA1

OA2

OA1

BRA

VSA

SRA

GND

SDO

SDI

SCK

SRB

CSN

CLK

5VOUT

ENN

Figure 2.1 TMC260/261 pin assignments (top view)

2.2 Signal Descriptions

Number

Type

Function

OA1

2, 3 7, 8

O (VS)

Bridge A1 output. Interconnect all of these pins using thick traces capable to carry the motor current and distribute heat into the PCB.

OA2

5, 6 10, 11

O (VS)

Bridge A2 output. Interconnect all of these pins using thick traces capable to carry the motor current and distribute heat into the PCB.

OB1

26, 27 31, 32

O (VS)

Bridge B1 output. Interconnect all of these pins using thick traces capable to carry the motor current and distribute heat into the PCB.

OB2

23, 24 28, 29

O (VS)

Bridge B2 output. Interconnect all of these pins using thick traces capable to carry the motor current and distribute heat into the PCB.

VSA VSB

4 30

Bridge A/B positive power supply. Connect to VS and provide sufficient filtering capacity for chopper current ripple.

BRA BRB

9 25

Bridge A/B negative power supply via sense resistor in bridge foot point.

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Number

Type

Function

SRA SRB

12 22

Sense resistor inputs for chopper current regulation.

5VOUT

13 Output of the on-chip 5V linear regulator. This voltage is used to supply the low-side MOSFETs and internal analog circuitry. An external capacitor to GND close to the pin is required. Place the capacitor near pins 13 and 17. A 470nF ceramic capacitor is sufficient.

SDO

DO VIO

SPI serial data output.

SDI (CFG3)

DI VIO

Data input of SPI interface / Microstep resolution control input in standalone mode: 0: MRES=256 microsteps; 1: MRES=16 microsteps with interpolation

SCK (CFG2)

DI VIO

Serial clock input of SPI interface / Chopper hysteresis control input in standalone mode: 0: HEND=4, HSTRT=2; 1: HEND=4, HSTRT=6

GND

17, 39, 44

Digital and analog low power GND.

CSN (CFG1)

DI VIO

Chip select input of SPI interface / Current control input in standalone mode: 0: Current scale CS=15; 1: Current scale CS=31

ENN

DI VIO

Power MOSFET enable input. All MOSFETs are switched off when disabled. (Active low.)

CLK

DI VIO

System clock input for all internal operations. Tie low to use the on-chip oscillator. A high signal disables the on-chip oscillator until power down.

VHS

35 High-side supply voltage (motor supply voltage - 10V)

36 Motor supply voltage

TST_ANA / ST_ALONE

AO/ DI VIO (pd)

non-C-Type: Leave open for normal operation. C-Type only: Tie to VCC_IO for non-SPI, stand-alone mode. Internal 10k pulldown resistor.

SG_TST

DO VIO

StallGuard2 output. Signals a motor stall. (Active high.)

VCC_IO

40 Input/output supply voltage VIO for all digital pins. Tie to digital logic supply voltage. Operation is allowed in 3.3V and 5V systems.

DIR

DI VIO

Direction input. Sampled on an active edge of the STEP input to determine stepping direction. Sampling a low increases the microstep counter, while sampling a high decreases the counter. A 60-ns internal glitch filter rejects short pulses on this input.

STEP

DI VIO

Step input. Active edges can be rising or both rising and falling, as controlled by the DEDGE mode bit. A 60-ns internal glitch filter rejects short pulses on this input.

TST_MODE

DI VIO

Test mode input. Puts IC into test mode. Tie to GND for normal operation.

n.c.

1, 33

No internal connection - can be tied to any net, e.g., in order to improve power routing to pins VSA and VSB.

n.c.

20, 34

No internal connection

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3 Internal Architecture

Figure 3.1 shows the internal architecture of TMC260 and TMC261.

VHS

5V linear regulator

5VOUT

470nF

GND

slope HS

slope LS

SRA

ENABLE

5V supply

TMC260C / TMC261C

OSC

15MHz

CSN

SCK

SDI

SDO

SENSE

SPI interface

Chopper

logic

SENSE

=150m for 1.8A peak (resp. 1A peak)

Provide sufficien t filtering capacity near bridge supp ly (electrolyt capacitors and ceramic capacito rs)

motor coil A

P-Gate

drivers

N-Gate

drivers

Break

before

make

VHS

+5V

DAC

VM-10V

linear

regulator

100n 16V

100n

Protection &

Diagnostics

slope HS

slope LS

SENSE

Chopper

logic

motor coil B

P-Gate

drivers

N-Gate

drivers

Break

before

make

VHS

+5V

DAC

ENABLE

Step &

Direction

interface

Step multiply

16 to 256

Sine wave

1024 entry

M U X

STEP

DIR

coolStep

Energy

efficiency

stallGuard 2

Clock

selector

CLK

SG_TST

Digital

control

SHORT

TO GND

BACK

EMF

CLK

8-20MHz

SIN &

COS

Phase polarity

VCC_IO

3.3V or 5V

100n

9-39V / 9-59V

step & dir

(optional)

stallGuard

output

TST_MODE

22R

Optional input pr otection and

filter network ag ainst inductive

sparks upon mo tor cable brea k

VSENSE

0.30V

0.16V

REF

OA1

OA2

VSA

BRA

SRB

BRB

OB2

OB1

VSB

10nF

Provide sufficien t filtering capacity near bridge supp ly (electrolyt

capacitors and cer amic capacitors)

ST_ALONE

/ TST_ANA

Open or GND for

SPI, VCC_IO for

stand-alone

SPI /

Stand-alone

configuration

Short

detectors

Short

detectors

Temp. sensor

100°C, 120°C,

136°C, 150°C

SENSE

=150m for 1.8A peak

(resp. 1A peak)

Figure 3.1 TMC260 and TMC261 block diagram

PROMINENT FEATURES INCLUDE:

Oscillator and clock selector

provide the system clock from the on-chip oscillator or an external source.

Step and direction interface

uses a microstep counter and sine table to generate target currents for the coils.

SPI interface

configures current setting, and chopper and optionally receives commands that directly set the coil current values.

Multiplexer

selects either the output of the sine table or the SPI interface for controlling the current into the motor coils.

Multipliers

scale down the currents to both coils when the currents are greater than those required by the load on the motor or as set by the CS current scale parameter.

DACs and comparators

convert the digital current values to analog signals that are compared with the voltages on the sense resistors. Comparator outputs terminate chopper drive phases when target currents are reached.

Break-before-make and gate drivers

ensure non-overlapping pulses, boost pulse voltage, and control pulse slope to the gates of the power MOSFETs.

On-chip voltage regulators

provide high-side voltage for P-channel MOSFET gate drivers and supply voltage for on-chip analog and digital circuits.

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4 Standalone Operation

Standalone operation is the easiest way to use the IC. In this mode, three pins configure for the most common settings. Just use the standard application circuit, tie low / high the SPI input pins to set the desired basic operation parameters and choose a sense resistor to fit the required motor current. However, advanced configuration and access to individual diagnostics only is possible via SPI.

CSN: SELECTION OF MOTOR CURRENT (USE FOR STANDSTILL CURRENT REDUCTION)

CSN (CFG1)

Chopper Setting

GND

Current Scale CS=15. Use for standstill current reduction, or to adapt lower sense resistor value.

VCC_IO

Current Scale CS=31. Maximum current. Control motor current by adapting sense resistors.

SCK: SELECTION OF CHOPPER HYSTERESIS (ADAPT FOR LOWEST MOTOR NOISE & VIBRATION)

SCK (CFG2)

Chopper Setting

GND

Low hysteresis (HSTRT=2, HEND=4), use for larger motor.

VCC_IO

Medium hysteresis (HSTRT=6, HEND=4), typical for Nema17 or smaller motor, or for high speed motors with high coil currents.

SDI: SELECTION OF MICROSTEP RESOLUTION (ADAPT TO STEP PULSE GENERATOR)

SDI (CFG3)

Chopper Setting

GND

256 Microsteps full resolution for Step/Dir interface

VCC_IO

16 Microsteps with internal interpolation to 256 microsteps

Half Bridge 2

Half Bridge 1

Half Bridge 2

VSA / B

2 x Current

Comparator

TMC260C / TMC261C

RSA / B

Sine Table

4*256 entry

2 x DAC

stallGuard2

coolStep

SG_TST

OA1

OA2

BRA / B

SENSERSENSE

OB1

OB2

Chopper

2 Phase

Stepper

Protection

& Diagnostics

STEP

DIR

SPI control,

Config & Diags

CSN/CFG1

SCK/CFG2

SDO

SDI/CFG3

Step Multiplier

VCC_IO

ST_ALONE

Stand Alone

CCIO

Current Hysteresis Microsteps

ENN

Enable/ Disable

Figure 2 Standalone configuration

Standalone mode automatically enables resonance dampening (EN_PFD) and 136°C overtemperature detection (OT_SENSE), sensitive high-side short detection (SHRTSENSE) and enable low side short protection (S2VS). Driver strength becomes set to SLPL=SLPH=3. TOFF is 4, TBL is 36 clocks in this mode. All other bits are cleared to 0. In standalone configuration, StallGuard level is fixed to SGT=2. This setting will work for homing with many 42mm and larger motors in a suitable velocity range. Adapt to full or half current as fitting using CSN configuration pin.

Resulting configuration words: SDI=0: $00200 / SDI=1: $00204 SCK=0: $90224 / SCK=1: $90264 CSN=0: $C020F / CSN=1: $C021F

$E810F, $A0000

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5 StallGuard2 Load Measurement

StallGuard2 provides an accurate measurement of the load on the motor. It can be used for stall detection as well as other uses at loads below those which stall the motor, such as CoolStep loadadaptive current reduction. (StallGuard2 is a more precise evolution of the earlier StallGuard technology.) The StallGuard2 measurement value changes linearly over a wide range of load, velocity, and current settings, as shown in Figure 5.1. At maximum motor load, the value goes to zero or near to zero. This corresponds to a load angle of 90° between the magnetic field of the coils and magnets in the rotor. This also is the most energy-efficient point of operation for the motor.

motor load

(% max. torque)

stallGuard2

reading

100

200

300

400

500

600

700

800

900

1000

0 10 20 30 40 50 60 70 80 90 100

Start value depends on motor and operating conditions

Motor stalls above this point. Load angle exceeds 90° and available torque sinks.

stallGuard value reaches zero and indicates danger of stall.

This point is set by stallGuard

threshold value SGT.

Figure 5.1 StallGuard2 load measurement SG as a function of load

Two parameters control StallGuard2 and one status value is returned.

Parameter

Description

Setting

Comment

SGT

7-bit signed integer that sets the StallGuard2 threshold level for asserting the SG_TST output and sets the optimum measurement range for readout. Negative values increase sensitivity, and positive values reduce sensitivity, so more torque is required to indicate a stall. Zero is a good starting value.

indifferent value

+1… +63

less sensitivity

-1… -64

higher sensitivity

SFILT

Mode bit which enables the StallGuard2 filter for more precision. If set, reduces the measurement frequency to one measurement per four fullsteps. If cleared, no filtering is performed. Filtering compensates for mechanical asymmetries in the construction of the motor, but at the expense of response time. Unfiltered operation is recommended for rapid stall detection. Filtered operation is recommended for more precise load measurement.

standard mode

filtered mode

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Status word

Description

Range

Comment

10-bit unsigned integer StallGuard2 measurement value. A higher value indicates lower mechanical load. A lower value indicates a higher load and therefore a higher load angle. For stall detection, adjust SGT to return an SG value of 0 or slightly higher upon maximum motor load before stall.

0… 1023

0: highest load low value: high load high value: less load

5.1 Tuning the StallGuard2 Threshold

Due to the dependency of the StallGuard2 value SG from motor-specific characteristics and applicationspecific demands on load and velocity the easiest way to tune the StallGuard2 threshold SGT for a specific motor type and operating conditions is interactive tuning in the actual application.

The procedure is:

1. Operate the motor at a reasonable velocity for your application and monitor SG.

2. Apply slowly increasing mechanical load to the motor. If the motor stalls before SG reaches

zero, decrease SGT. If SG reaches zero before the motor stalls, increase SGT. A good SGT starting value is zero. SGT is signed, so it can have negative or positive values.

3. The optimum setting is reached when SG is between 0 and 400 at increasing load shortly

before the motor stalls, and SG increases by 100 or more without load. SGT in most cases can be tuned together with the motion velocity in a way that SG goes to zero when the motor stalls and the stall output SG_TST is asserted. This indicates that a step has been lost.

The system clock frequency affects SG. An external crystal-stabilized clock should be used for applications that demand the highest precision. The power supply voltage also affects SG, so tighter regulation results in more accurate values. SG measurement has a high resolution, and there are a few ways to enhance its accuracy, as described in the following sections.

5.1.1 Variable Velocity Operation

Across a range of velocities, on-the-fly adjustment of the StallGuard2 threshold SGT improves the accuracy of the load measurement SG. This also improves the power reduction provided by CoolStep, which is driven by SG. Linear interpolation between two SGT values optimized at different velocities is a simple algorithm for obtaining most of the benefits of on-the-fly SGT adjustment, as shown in Figure 5.2. An optimal SGT curve in black and a two-point interpolated SGT curve in red are shown.

back EMF reaches

supply voltage

optimum

SGT setting

Motor RPM

(200 FS motor)

stallGuard2

reading at

no load

100

200

300

400

500

600

700

800

900

10001820

0 0 50 100 150 200 250 300 350 400 450 500 550 600

lower limit for stall

detection 4 RPM

simplified

SGT setting

Figure 5.2 Linear interpolation for optimizing SGT with changes in velocity.

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5.1.2 Small Motors with High Torque Ripple and Resonance

Motors with a high detent torque show an increased variation of the StallGuard2 measurement value SG with varying motor currents, especially at low currents. For these motors, the current dependency might need correction in a similar manner to velocity correction for obtaining the highest accuracy.

5.1.3 Temperature Dependence of Motor Coil Resistance

Motors working over a wide temperature range may require temperature correction, because motor coil resistance increases with rising temperature. This can be corrected as a linear reduction of SG at increasing temperature, as motor efficiency is reduced.

5.1.4 Accuracy and Reproducibility of StallGuard2 Measurement

In a production environment, it may be desirable to use a fixed SGT value within an application for one motor type. Most of the unit-to-unit variation in StallGuard2 measurements results from manufacturing tolerances in motor construction. The measurement error of StallGuard2 – provided that all other parameters remain stable – can be as low as:

  󰇛󰇜

5.2 StallGuard2 Measurement Frequency and Filtering

The StallGuard2 measurement value SG is updated with each full step of the motor. This is enough to safely detect a stall, because a stall always means the loss of four full steps. In a practical application, especially when using CoolStep, a more precise measurement might be more important than an update for each fullstep because the mechanical load never changes instantaneously from one step to the next. For these applications, the SFILT bit enables a filtering function over four load measurements. The filter should always be enabled when high-precision measurement is required. It compensates for variations in motor construction, for example due to misalignment of the phase A to phase B magnets. The filter should only be disabled when rapid response to increasing load is required, such as for stall detection at high velocity.

5.3 Detecting a Motor Stall

To safely detect a motor stall, a stall threshold must be determined using a specific SGT setting. Therefore, you need to determine the maximum load the motor can drive without stalling and to monitor the SG value at this load, for example some value within the range 0 to 400. The stall threshold should be a value safely within the operating limits, to allow for parameter stray. So, your microcontroller software should set a stall threshold which is slightly higher than the minimum value seen before an actual motor stall occurs. The response at an SGT setting at or near 0 gives some idea on the quality of the signal: Check the SG value without load and with maximum load. These values should show a difference of at least 100 or a few 100, which shall be large compared to the offset. If you set the SGT value so that a reading of 0 occurs at maximum motor load, an active high stall output signal will be available at SG_TST output.

5.4 Limits of StallGuard2 Operation

StallGuard2 does not operate reliably at extreme motor velocities: Very low motor velocities (for many motors, less than one revolution per second) generate a low back EMF and make the measurement unstable and dependent on environment conditions (temperature, etc.). Other conditions will also lead to extreme settings of SGT and poor response of the measurement value SG to the motor load.

Very high motor velocities, in which the full sinusoidal current is not driven into the motor coils also lead to poor response. These velocities are typically characterized by the motor back EMF reaching the supply voltage.

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6 CoolStep Load-Adaptive Current Control

CoolStep allows substantial energy savings, especially for motors which see varying loads or operate at a high duty cycle. Because a stepper motor application needs to work with a torque reserve of 30% to 50%, even a constant-load application allows significant energy savings because CoolStep automatically enables torque reserve when required. Reducing power consumption keeps the system cooler, increases motor life, and allows reducing cost in the power supply and cooling components.

Hint

Reducing motor current by half results in reducing power by a factor of four.

Energy efficiency - power consumption decreased up to 75%. Motor generates less heat - improved mechanical precision. Less cooling infrastructure - for motor and driver. Cheaper motor - does the job.

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

0 50 100 150 200 250 300 350

Efficiency

Velocity [RPM]

Efficiency with coolStep

Efficiency with 50% torque reserve

Figure 6.1 Energy efficiency example with CoolStep

Figure 6.1 shows the efficiency gain of a 42mm stepper motor when using CoolStep compared to standard operation with 50% of torque reserve. CoolStep is enabled above 60rpm in the example.

CoolStep is controlled by several parameters, but two are critical for understanding how it works:

Parameter

Description

Range

Comment

SEMIN

4-bit unsigned integer that sets a lower threshold. If SG goes below this threshold, CoolStep increases the current to both coils. The 4-bit SEMIN value is scaled by 32 to cover the lower half of the range of the 10-bit SG value. (The name of this parameter is derived from smartEnergy, which is an earlier name for CoolStep.)

0… 15

lower CoolStep threshold: SEMINx32 SEMAX

4-bit unsigned integer that controls an upper threshold. If SG is sampled equal to or above this threshold enough times, CoolStep decreases the current to both coils. The upper threshold is (SEMIN + SEMAX + 1) x 32.

0… 15

upper CoolStep threshold: (SEMIN+SEMAX+1)x32

Figure 6.2 shows the operating regions of CoolStep. The black line represents the SG measurement value, the blue line represents the mechanical load applied to the motor, and the red line represents

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the current into the motor coils. When the load increases, SG falls below SEMIN, and CoolStep increases the current. When the load decreases and SG rises above (SEMIN + SEMAX + 1) x 32 the current becomes reduced.

stallGuard2

reading

0=maximum load

motor current increment area

motor current reduction area

stall possible

SEMIN

SEMAX+SEMIN+1

time

motor current

current setting CS (upper limit)

½ or ¼ CS (lower limit)

mechanical load

current increment due to

increased load

slow current reduction due

to reduced motor load

load angle optimized load angle optimized

load

angle

optimized

Figure 6.2 CoolStep adapts motor current to the load.

Four more parameters control CoolStep and one status value is returned:

Parameter

Description

Range

Comment

Current scale. Scales both coil current values as taken from the internal sine wave table or from the SPI interface. For high precision motor operation, work with a current scaling factor in the range 16 to 31, because scaling down the current values reduces the effective microstep resolution by making microsteps coarser. This setting also controls the maximum current value set by CoolStep™.

0… 31

scaling factor: 1/32, 2/32, … 32/32

SEUP

Number of increments of the coil current for each occurrence of an SG measurement below the lower threshold.

0… 3

step width is: 1, 2, 4, 8

SEDN

Number of occurrences of SG measurements above the upper threshold before the coil current is decremented.

0… 3

number of StallGuard measurements per decrement: 32, 8, 2, 1

SEIMIN

Mode bit that controls the lower limit for scaling the coil current. If the bit is set, the limit is ¼ CS. If the bit is clear, the limit is ½ CS.

0 Minimum motor current: 1/2 of CS

1/4 of CS

Status word

Description

Range

Comment

5-bit unsigned integer reporting the actual current scaling value determined by CoolStep. This value is biased by 1 and divided by 32, so the range is 1/32 to 32/32. The value will not be greater than the value of CS or lower than either ¼ CS or ½ CS depending on SEIMIN setting.

0… 31

Actual motor current scaling factor set by CoolStep: 1/32, 2/32, … 32/32

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6.1 Tuning CoolStep

Before tuning CoolStep, first tune the StallGuard2 threshold level SGT, which affects the range of the load measurement value SG. CoolStep uses SG to operate the motor near the optimum load angle of +90°.

The current increment speed is specified in SEUP, and the current decrement speed is specified in SEDN. They can be tuned separately because they are triggered by different events that may need different responses. The encodings for these parameters allow the coil currents to be increased much more quickly than decreased, because crossing the lower threshold is a more serious event that may require a faster response. If the response is too slow, the motor may stall. In contrast, a slow response to crossing the upper threshold does not risk anything more serious than missing an opportunity to save power.

Hint

CoolStep operates between limits controlled by the current scale parameter CS and the SEIMIN bit.

6.1.1 Response Time

For fast response to increasing motor load, use a high current increment step SEUP. If the motor load changes slowly, a lower current increment step can be used to avoid motor current oscillations. If the filter controlled by SFILT is enabled, the measurement rate and regulation speed are cut by a factor of four.

6.1.2 Low Velocity and Standby Operation

Because StallGuard2 is not able to measure the motor load in standstill and at very low RPM, the current at low velocities should be set to an application-specific default value and combined with standstill current reduction settings programmed through the SPI interface.

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7 SPI Interface

The TMC260 and TMC261 allow full control over all configuration parameters and mode bits through the SPI interface. An initialization is required prior to motor operation. The SPI interface also allows reading back status values and bits.

7.1 Bus Signals

The SPI bus on the TMC260 and the TMC261 has four signals:

SCK bus clock input SDI serial data input SDO serial data output CSN chip select input (active low)

The slave is enabled for an SPI transaction by a low on the chip select input CSN. Bit transfer is synchronous to the bus clock SCK, with the slave latching the data from SDI on the rising edge of SCK and driving data to SDO following the falling edge. The most significant bit is sent first. A minimum of 20 SCK clock cycles is required for a bus transaction with the TMC260 and the TMC261.

If more than 20 clocks are driven, the additional bits shifted into SDI are shifted out on SDO after a 20-clock delay through an internal shift register. This can be used for daisy chaining multiple chips.

CSN must be low during the whole bus transaction. When CSN goes high, the contents of the internal shift register are latched into the internal control register and recognized as a command from the master to the slave. If more than 20 bits are sent, only the last 20 bits received before the rising edge of CSN are recognized as the command.

7.2 Bus Timing

SPI interface is synchronized to the internal system clock, which limits the SPI bus clock SCK to half of the system clock frequency. If the system clock is based on the on-chip oscillator, an additional 10% safety margin must be used to ensure reliable data transmission. All SPI inputs as well as the ENN input are internally filtered to avoid triggering on pulses shorter than 20ns. Figure 7.1 shows the timing parameters of an SPI bus transaction, and the table below specifies their values.

CSN

SCK

SDI

SDO

bit19 bit18 bit0

Figure 7.1 SPI Timing

Hint

Usually this SPI timing is referred to as SPI MODE 3. Data change is at the negative SCK edge, and SCK return to high level. CSN spans the complete 20 Bit transmission.

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SPI Interface Timing

AC-Characteristics

clock period is t

CLK

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

SCK valid before or after change of CSN

tCC 10

CSN high time

CSH

Min time is for synchronous CLK with SCK high one tCH before CSN high only

CLK

>2t

CLK

+10

SCK low time

tCL

Min time is for synchronous CLK only

CLK

+10

SCK high time

tCH

Min time is for synchronous CLK only

CLK

+10

SCK frequency using internal clock

SCK

Assumes minimum OSC frequency

MHz

SCK frequency using external 16MHz clock

SCK

Assumes synchronous CLK

MHz

SDI setup time before rising edge of SCK

tDU 10

SDI hold time after rising edge of SCK

tDH 10

Data out valid time after falling SCK clock edge

tDO

No capacitive load on SDO

FILT

SDI, SCK, and CSN filter delay time

FILT

Rising and falling edge

7.3 Bus Architecture

SPI slaves can be chained and used with a single chip select line. If slaves are chained, they behave like a long shift register. For example, a chain of two motor drivers requires 40 bits to be sent. The last bits shifted to each register in the chain are loaded into an internal register on the rising edge of the CSN input. For example, 24 or 32 bits can be sent to a single motor driver, but it latches just the last 20 bits received before CSN goes high.

Driver 3

Half Bridge 2

Half Bridge 1

Half Bridge 2

VSA / B

2 x current comparator

2 phase stepper motor

TMC260 / TMC261 stepper driver IC

RSA / B

Protection

& diagnostics

sine table

4*256 entry

STEP

DIR

2 x DAC

SPI control,

Config & diags

CSN

SCK

SDO

SDI

stallGuard2™

coolStep™

step multiplier

SG_TST

OA1

OA2

BRA / B

SENSERSENSE

OB1

OB2

chopper

VCC_IO

TMC429 triple stepper motor controller

SPI to master

nSCS_C

SCK_C

SDOZ_C

SDI_C

CLK

3x linear RAMP

generator

Position

comparator

Interrupt controller

nINT

Reference switch

processing

Step &

Direction pulse

generation

Output select

SPI or

Step & Dir

Microstep table

Serial driver

interface

POSCOMP

3 x REF_L, REF_R

S1 (SDO_S)

D1 (SCK_S)

S2 (nSCS_S)

D2 (SDI_S)

S3 (nSCS_2)

D3 (nSCS_3)

Driver 2

Real time Step & Dir interface

User CPU

Motion command SPI

(TM)

Configuration and diagnostics SPI

(TM)

Mechanical Feedback or

virtual stop switch

Realtime event trigger Virtual stop switch

Stepper #1

Third driver and motor

Second driver and motor

System interfacing

System control

Motion control

motor driver

Figure 7.2 Interfaces to a TMC429 motion controller chip and a TMC260 or TMC261 motor driver

Figure 7.2 shows the interfaces in a typical application. The SPI bus is used by an embedded MCU to initialize the control registers of both a motion controller and one or more motor drivers. STEP/DIR interfaces are used between the motion controller and the motor drivers.

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7.4 Register Write Commands

An SPI bus transaction to the TMC260 or TMC261 is a write command to one of the five write-only registers that hold configuration parameters and mode bits:

Description

Driver Control Register (DRVCTRL)

The DRVCTRL register has different formats for controlling the interface to the motion controller depending on whether or not the STEP/DIR interface is enabled.

Chopper Configuration Register (CHOPCONF)

The CHOPCONF register holds chopper parameters and mode bits.

CoolStep Configuration Register (SMARTEN)

The SMARTEN register holds CoolStep parameters and a mode bit. (smartEnergy is an earlier name for CoolStep.)

StallGuard2 Configuration Register (SGCSCONF)

The SGCSCONF register holds StallGuard2 parameters and a mode bit.

Driver Configuration Register (DRVCONF)

The DRVCONF register holds parameters and mode bits used to control the power MOSFETs and the protection circuitry. It also holds the SDOFF bit which controls the STEP/DIR interface and the RDSEL parameter which controls the contents of the response returned in an SPI transaction.

In the following sections, multibit binary values are prefixed with a % sign, for example %0111.

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7.4.1 Write Command Overview

The table below shows the formats for the five register write commands. Bits 19, 18, and sometimes 17 select the register being written, as shown in bold. The DRVCTRL register has two formats, as selected by the SDOFF bit. Bits shown as 0 must always be written as 0, and bits shown as 1 must always be written with 1. Detailed descriptions of each parameter and mode bit are given in the following sections.

Bit

DRVCTRL (SDOFF=1)

DRVCTRL (SDOFF=0)

CHOPCONF

SMARTEN

SGCSCONF

DRVCONF

0 0 1 1 1 1 18

0 0 0 0 1

PHA 0 0 1 0

CA7 0 TBL1

SFILT

TST

CA6 0 TBL0

SEIMIN

SLPH1

CA5 0 CHM

SEDN1

SGT6

SLPH0

CA4 0 RNDTF

SEDN0

SGT5

SLPL1

CA3 0 HDEC1

SGT4

SLPL0

CA2 0 HDEC0

SEMAX3

SGT3

CA1 0 HEND3

SEMAX2

SGT2

DISS2G

CA0

INTPOL

HEND2

SEMAX1

SGT1

TS2G1

PHB

DEDGE

HEND1

SEMAX0

SGT0

TS2G0

CB7 0 HEND0

0 0 SDOFF

CB6 0 HSTRT2

SEUP1

VSENSE

CB5 0 HSTRT1

SEUP0

RDSEL1

CB4 0 HSTRT0

CS4

RDSEL0

CB3

MRES3

TOFF3

SEMIN3

CS3

OTSENS *)

CB2

MRES2

TOFF2

SEMIN2

CS2

SHRTSENS *)

CB1

MRES1

TOFF1

SEMIN1

CS1

EN_PFD *)

CB0

MRES0

TOFF0

SEMIN0

CS0

EN_S2VS *)

*) Additional option for -C types only. Setting these bits for non-C-types does not have any effect.

7.4.2 Read Response Overview

The table below shows the formats for the read response. The RDSEL parameter in the DRVCONF register selects the format of the read response.

Bit

RDSEL=%00

RDSEL=%01

RDSEL=%10

RDSEL=%11*)

MSTEP9

SG9

UV_7V

MSTEP8

SG8

ENN input

MSTEP7

SG7

S2VSB

MSTEP6

SG6

S2GB

MSTEP5

SG5

S2VSA

MSTEP4

SG4

SE4

S2GA

MSTEP3

SG3

SE3

OT150

MSTEP2

SG2

SE2

OT136

MSTEP1

SG1

SE1

OT120

MSTEP0

SG0

SE0

OT100

0 0 0

STST

OLB

OLA

SHORTB (S2GB for non-C-type)

SHORTA (S2GA for non-C-type)

OTPW

OT 0 SG

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7.5 Driver Control Register (DRVCTRL)

The format of the DRVCTRL register depends on the state of the SDOFF mode bit.

SPI Mode SDOFF bit is set, the STEP/DIR interface is disabled, and DRVCTRL is the interface for

specifying the currents through each coil.

STEP/DIR Mode SDOFF bit is clear, the STEP/DIR interface is enabled, and DRVCTRL is a configuration

7.5.1 DRVCTRL Register in SPI Mode

DRVCTRL

Driver Control in SPI Mode (SDOFF=1)

Bit

Name

Function

Comment

19 0 Register address bit

18 0 Register address bit

PHA

Polarity A

Sign of current flow through coil A: 0: Current flows from OA1 pins to OA2 pins. 1: Current flows from OA2 pins to OA1 pins.

CA7

Current A MSB

Magnitude of current flow through coil A. The range is 0 to 248, if hysteresis or offset are used up to their full extent. The resulting value after applying hysteresis or offset must not exceed 255.

CA6

CA5

CA4 12

CA3

CA2

CA1 9

CA0

Current A LSB

PHB

Polarity B

Sign of current flow through coil B: 0: Current flows from OB1 pins to OB2 pins. 1: Current flows from OB2 pins to OB1 pins.

CB7

Current B MSB

Magnitude of current flow through coil B. The range is 0 to 248, if hysteresis or offset are used up to their full extent. The resulting value after applying hysteresis or offset must not exceed 255.

CB6

CB5

CB4 3

CB3

CB2

CB1 0

CB0

Current B LSB

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7.5.2 DRVCTRL Register in STEP/DIR Mode

DRVCTRL

Driver Control in STEP/DIR Mode (SDOFF=0)

Bit

Name

Function

Comment

19 0 Register address bit

18 0 Register address bit

17 0 Reserved

16 0 Reserved

15 0 Reserved

14 0 Reserved

13 0 Reserved

12 0 Reserved

11 0 Reserved

10 0 Reserved

INTPOL

Enable STEP interpolation

0: Disable STEP pulse interpolation. 1: Enable STEP pulse multiplication by 16.

DEDGE

Enable double edge STEP pulses

0: Rising STEP pulse edge is active, falling edge is inactive. 1: Both rising and falling STEP pulse edges are active.

7 0 Reserved

6 0

Reserved

5 0 Reserved

4 0 Reserved

3 MRES3

Microstep resolution for STEP/DIR mode

Microsteps per 90°: %0000: 256 %0001: 128 %0010: 64 %0011: 32 %0100: 16 %0101: 8 %0110: 4 %0111: 2 (halfstep) %1000: 1 (fullstep)

MRES2

MRES1

MRES0

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7.6 Chopper Control Register (CHOPCONF)

CHOPCONF

Chopper Configuration

Bit

Name

Function

Comment

19 1 Register address bit

18 0 Register address bit

17 0 Register address bit

TBL1

Blanking time

Blanking time interval, in system clock periods: %00: 16 %01: 24 %10: 36 %11: 54

TBL0

CHM

Chopper mode

This mode bit affects the interpretation of the HDEC, HEND, and HSTRT parameters shown below.

Standard mode (SpreadCycle)

Constant t

OFF

with fast decay time. Fast decay time is also terminated when the negative nominal current is reached. Fast decay is after on time.

RNDTF

Random TOFF time

Enable randomizing the slow decay phase duration: 0: Chopper off time is fixed as set by bits t

OFF

1: Random mode, t

OFF

is random modulated by

CLK

= -12 … +3 clocks.

HDEC1

Hysteresis decrement interval or Fast decay mode

CHM=0

Hysteresis decrement period setting, in system clock periods: %00: 16 %01: 32 %10: 48 %11: 64

HDEC0

CHM=1 HDEC1=0: current comparator can terminate the fast decay phase before timer expires. HDEC1=1: only the timer terminates the fast decay phase.

HDEC0: MSB of fast decay time setting.

HEND3

Hysteresis end (low) value or Sine wave offset

CHM=0

%0000 … %1111: Hysteresis is -3, -2, -1, 0, 1, …, 12 (1/512 of this setting adds to current setting) This is the hysteresis value which becomes used for the hysteresis chopper.

HEND2

HEND1

CHM=1

%0000 … %1111: Offset is -3, -2, -1, 0, 1, …, 12 This is the sine wave offset and 1/512 of the value becomes added to the absolute value of each sine wave entry.

HEND0

HSTRT2

Hysteresis start value or Fast decay time setting CHM=0

Hysteresis start offset from HEND: %000: 1 %100: 5 %001: 2 %101: 6 %010: 3 %110: 7 %011: 4 %111: 8

Effective: HEND+HSTRT must be ≤ 15

HSTRT1

HSTRT0

CHM=1

Three least-significant bits of the duration of the fast decay phase. The MSB is HDEC0. Fast decay time is a multiple of system clock periods: N

CLK

= 32 x (HDEC0+HSTRT)

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CHOPCONF

Chopper Configuration

Bit

Name

Function

Comment

TOFF3

Off time/MOSFET disable

Duration of slow decay phase. If TOFF is 0, the MOSFETs are shut off. If TOFF is nonzero, slow decay time is a multiple of system clock periods: N

CLK

= 24 + (32 x TOFF) %0000: Driver disable, all bridges off %0001: 1 (use with TBL of minimum 24 clocks) %0010 … %1111: 2 … 15

TOFF2

TOFF1

TOFF0

7.7 CoolStep Control Register (SMARTEN)

SMARTEN

CoolStep Configuration

Bit

Name

Function

Comment

19 1 Register address bit

18 0 Register address bit

17 1 Register address bit

16 0 Reserved

SEIMIN

Minimum CoolStep current

0: ½ CS current setting 1: ¼ CS current setting

SEDN1

Current decrement speed

Number of times that the StallGuard2 value must be sampled equal to or above the upper threshold for each decrement of the coil current: %00: 32 %01: 8 %10: 2 %11: 1

SEDN0

12 0 Reserved

SEMAX3

Upper CoolStep threshold as an offset from the lower threshold

If the StallGuard2 measurement value SG is sampled equal to or above (SEMIN+SEMAX+1) x 32 enough times, then the coil current scaling factor is decremented.

SEMAX2

SEMAX1

SEMAX0

7 0 Reserved

6 SEUP1

Current increment size

Number of current increment steps for each time that the StallGuard2 value SG is sampled below the lower threshold: %00: 1 %01: 2 %10: 4 %11: 8

SEUP0

4 0 Reserved

SEMIN3

Lower CoolStep threshold/CoolStep disable

If SEMIN is 0, CoolStep is disabled. If SEMIN is nonzero and the StallGuard2 value SG falls below SEMIN x 32, the CoolStep current scaling factor is increased.

SEMIN2

SEMIN1

SEMIN0

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7.8 StallGuard2 Control Register (SGCSCONF)

SGCSCONF

StallGuard2™ and Current Setting

Bit

Name

Function

Comment

19 1 Register address bit

18 1 Register address bit

17 0 Register address bit

SFILT

StallGuard2 filter enable

0: Standard mode, fastest response time. 1: Filtered mode, updated once for each four fullsteps to compensate for variation in motor construction, highest accuracy.

15 0 Reserved

SGT6

StallGuard2 threshold value

The StallGuard2 threshold value controls the optimum measurement range for readout and stall indicator output (SG_TST). A lower value results in a higher sensitivity and less torque is required to indicate a stall. The value is a two’s complement signed integer. Range: -64 to +63

SGT5

SGT4

SGT3

SGT2

SGT1

SGT0

7 0 Reserved

6 0 Reserved

5 0

Reserved

CS4

Current scale (scales digital currents A and B)

Current scaling for SPI and step/direction operation. %00000 … %11111: 1/32, 2/32, 3/32, … 32/32 This value is biased by 1 and divided by 32, so the range is 1/32 to 32/32. Example: CS=20 is 21/32 current

CS3 2 CS2

CS1

CS0

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7.9 Driver Control Register (DRVCONF)

DRVCONF

Driver Configuration

Bit

Name

Function

Comment

19 1 Register address bit

18 1 Register address bit

17 1 Register address bit

TST

Reserved TEST mode

Must be cleared for normal operation. When set, the SG_TST output exposes digital test values, and the TEST_ANA output exposes analog test values.

SLPH1

Slope control, high side

%00: Minimum %01: Minimum (+tc) %10: Medium (+tc) %11: Maximum Temperature compensated mode (tc) increases the highside MOSFET gate driver strength if the overtemperature warning temperature is reached. This compensates for temperature dependency of high-side slope control.

SLPH0

SLPL1

Slope control, low side

SLPL0

11 0 Reserved

Set to 0

DISS2G

Short to GND protection disable

0: Short to GND protection is enabled. 1: Short to GND protection is disabled.

TS2G1

Short to GND detection timer

%00: 3.2µs. %01: 1.6µs. %10: 1.2µs. %11: 0.8µs.

TS2G0

SDOFF

STEP/DIR interface disable

0: Enable STEP and DIR interface. 1: Disable STEP and DIR interface. SPI interface is used to move motor.

VSENSE

Sense resistor voltage-based current scaling

0: Full-scale sense resistor voltage is 310mV. 1: Full-scale sense resistor voltage is 165mV. (Full-scale refers to a current setting of 31 and a DAC value of 255.)

RDSEL1

Select value for read out (RD bits)

%00

Microstep position read back

RDSEL0

%01

StallGuard2 level read back

%10

StallGuard2 & CoolStep current level read back

%11 *)

All status flags and detectors

OTSENS *)

Overtemperature sensitivity

0: Shutdown at 150°C 1: Sensitive shutdown at 136°C

SHRTSENS *)

Short to GND detection sensitivity

0: Low sensitivity 1: High sensitivity – better protection for high side FETs

EN_PFD *)

Enable Passive fast decay / 5V undervoltage threshold

0: No additional motor dampening. 1: Motor dampening to reduce motor resonance at medium velocity. In addition, this bit reduces the lower nominal operation voltage limit from 7V to 4.5V

EN_S2VS *)

Enable short to VS & CLK fail protection

0: Short to VS and clock failsafe protection disabled 1: Short to VS / overcurrent protection enabled. In addition, enables protection against clock input CLK fail, when using an external clock source.

*) These bits have a function for -C types only. Setting these bits / functions for non-C-types does not have any effect. The TMC260 and TMC260C, resp. TMC261 and TMC261C behave identically with setting

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7.10 Read Response

For every write command sent to the motor driver, a 20-bit response is returned to the motion controller. The response has one of three formats, as selected by the RDSEL parameter in the DRVCONF register. The table below shows these formats. Software must not depend on the value of any bit shown as reserved.

DRVSTATUS

Read Response

Bit

Name

Function

Comment

RDSEL

%00

%01

%10

%11

MSTEP9

SG9

UV_7V

Microstep counter / StallGuard2 SG9:0 / StallGuard2 SG9:5 and CoolStep SE4:0 / Diagnostic status

Microstep position in sine table for coil A in STEP/DIR mode. MSTEP9 is the Polarity bit: 0: Current flows from OA1 pins to OA2 pins. 1: Current flows from OA2 pins to OA1 pins.

MSTEP8

SG8

ENN in

MSTEP7

SG7

S2VSB

MSTEP6

SG6

S2GB

MSTEP5

SG5

S2VSA

StallGuard2 value SG9:0.

MSTEP4

SG4

SE4

S2GA

StallGuard2 value SG9:5 and the actual CoolStep scaling value SE4:0.

MSTEP3

SG3

SE3

OT150

MSTEP2

SG2

SE2

OT136

Full diagnostic: <7V VS flag, state of ENN input, individual short to GND and short to VS flags, temperature detector readout

MSTEP1

SG1

SE1

OT120

MSTEP0

SG0

SE0

OT100

9 0 1

%11 response allows to distinguish -C type. Non-C-type delivers %00 in each case.

8 0 1

STST

Standstill indicator

0: No standstill condition detected. 1: No active edge occurred on the STEP input during the last 220 system clock cycles.

OLB

Open load indicator

0: No open load condition detected. 1: No chopper event has happened during the last period with constant coil polarity. Only a current above 1/16 of the maximum setting can clear this bit! Hint: This bit is only a status indicator. The chip takes no other action when this bit is set. False indications may occur during fast motion and at standstill. Check this bit only during slow motion.

OLA

SHORTB

Short detection status

0: No short condition. 1: Short condition. The short counter is incremented by each short circuit and the chopper cycle is suspended. The counter is decremented for each phase polarity change. The MOSFETs are shut off when the counter reaches 3 and remain shut off until the shutdown condition is cleared by disabling and re-enabling the driver. The shutdown condition becomes reset by de-asserting the ENN input or clearing the TOFF parameter.

SHORTA

OTPW

Overtemp. warning

0: No overtemperature warning condition. 1: Warning threshold is active.

Overtemp. shutdown

0: No overtemperature shutdown condition. 1: Overtemperature shutdown has occurred.

StallGuard2 status

0: No motor stall detected. 1: StallGuard2 threshold has been reached,

and the SG_TST output is driven high.

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7.11 Device Initialization

The following sequence of SPI commands is an example of enabling the driver and initializing the chopper:

SPI = $901B4; // Hysteresis mode

SPI = $94557; // Constant t

off

mode

SPI = $D001F; // Current setting: $d001F (max. current)

SPI = $E0010; // low driver strength, StallGuard2 read, SDOFF=0

SPI = $00000; // 256 microstep setting

First test of CoolStep current control:

SPI = $A8202; // Enable CoolStep with minimum current ¼ CS

The configuration parameters should be tuned to the motor and application for optimum performance.

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8 STEP/DIR Interface

The STEP and DIR inputs provide a simple, standard interface compatible with many existing motion controllers. The MicroPlyer STEP pulse interpolator brings the smooth motor operation of highresolution microstepping to applications originally designed for coarser stepping and reduces pulse bandwidth.

8.1 Timing

Figure 8.1 shows the timing parameters for the STEP and DIR signals, and the table below gives their specifications. When the DEDGE mode bit in the DRVCTRL register is set, both edges of STEP are active. If DEDGE is cleared, only rising edges are active. STEP and DIR are sampled and synchronized to the system clock. An internal analog filter removes glitches on the signals, such as those caused by long PCB traces. If the signal source is far from the chip, and especially if the signals are carried on cables, the signals should be filtered or differentially transmitted.

DIR

STEP

DSH

DSU

Active edge

(DEDGE=0)

Active edge

(DEDGE=0)

Figure 8.1 STEP and DIR timing.

STEP and DIR Interface Timing

AC-Characteristics

clock period is t

CLK

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Step frequency (at maximum microstep resolution)

STEP

DEDGE=0

½ f

CLK

DEDGE=1

¼ f

CLK

Fullstep frequency

fFS f

CLK

/512

STEP input low time

tSL

max(t

FILTSD

CLK

+20)

STEP input high time

max(t

FILTSD

CLK

+20)

DIR to STEP setup time

DSU

DIR after STEP hold time

DSH

STEP and DIR spike filtering time TMC2660C *)

FILTSD

Rising and falling edge

STEP and DIR sampling relative to rising CLK input

SDCLKHI

Before rising edge of CLK

FILTSD

*) The -C type has reduced filter time in order to reduce the danger of skipped step pulses

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8.2 Microstep Table

The internal microstep table maps the sine function from 0° to 90°, and symmetries allow mapping the sine and cosine functions from 0° to 360° with this table. The angle is encoded as a 10-bit unsigned integer MSTEP provided by the microstep counter. The size of the increment applied to the counter while microstepping through this table is controlled by the microstep resolution setting MRES in the DRVCTRL register. Depending on the DIR input, the microstep counter is increased (DIR=0) or decreased (DIR=1) by the step size with each STEP active edge. Despite many entries in the last quarter of the table being equal, the electrical angle continuously changes, because either the sine wave or cosine wave is in an area, where the current vector changes monotonically from position to position. Figure 8.2 shows the table. The largest values are 248, which leaves headroom used for adding an offset.

Entry

0-31

32-63

64-95

96-127

128-159

160-191

192-223

224-255 0 1

138

176

207

229

243

140

177

207

230

244

141

178

208

231

244 3 5

100

142

179

209

231

244

101

143

180

210

232

244

103

145

181

211

232

245 6 10

104

146

182

212

233

245

105

147

183

212

233

245

107

148

184

213

234

245 9 14

108

150

185

214

234

246

109

151

186

215

235

246

111

152

187

215

235

246

112

153

188

216

236

246

114

154

189

217

236

246

115

156

190

218

237

247

116

157

191

218

237

247

118

158

192

219

238

247

119

159

193

220

238

247

120

160

194

220

238

247

122

161

195

221

239

247

123

163

196

222

239

247

124

164

197

223

240

247

126

165

198

223

240

248

127

166

199

224

240

248

128

167

200

225

241

248

129

168

201

225

241

248

131

169

201

226

241

248

132

170

202

226

242

248

133

172

203

227

242

248

135

173

204

228

242

248

136

174

205

228

243

248

137

175

206

229

243

248

Figure 8.2 Internal microstep table showing the first quarter of the sine wave.

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8.3 Changing Resolution

The application may need to change the microstepping resolution to get the best performance from the motor. For example, high-resolution microstepping may be used for precision operations on a workpiece, and then fullstepping may be used for maximum torque at maximum velocity to advance to the next workpiece. When changing to coarse resolutions like fullstepping or halfstepping, switching should occur at or near positions that correspond to steps in the lower resolution, as shown in Table 8.1.

Step Position

MSTEP Value

Coil A Current

Coil B Current

Half step 0 0 0%

100%

Full step 0

128

70.7%

Half step 1

256

100%

Full step 1

384

70.7%

-70.7%

Half step 2

512

-100%

Full step 2

640

-70.7%

Half step 3

768

-100%

Full step 3

896

-70.7%

70.7%

Table 8.1 Optimum positions for changing to halfstep and fullstep resolution

8.4 MicroPlyer Step Interpolator

For each active edge on STEP, MicroPlyer produces 16 microsteps at 256x resolution, as shown in Figure 8.3. MicroPlyer is enabled by setting the INTPOL bit in the DRVCTRL register. It supports input at 16x resolution, which it transforms into 256x resolution. The step rate for each 16 microsteps is determined by measuring the time interval of the previous step period and dividing it into 16 equal parts. The maximum time between two microsteps corresponds to 220 (roughly one million system clock cycles), for an even distribution of 1/256 microsteps. At 16MHz system clock frequency, this results in a minimum step input frequency of 16Hz for MicroPlyer operation (one fullstep per second). A lower step rate causes the STST bit to be set, which indicates a standstill event. At that frequency,

microsteps occur at a rate of







   .

Attention

MicroPlyer only works well with a stable STEP frequency. Do not use the DEDGE option if the STEP signal does not have a 50% duty cycle.

STEP

interpolated

microstep

Active edge

(DEDGE=0)

Active edge

(DEDGE=0)

Active edge

(DEDGE=0)

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 32

Active edge

(DEDGE=0)

STANDSTILL

(STST) active

33 34 35 36 37 38 39 4041 42 43 44 45 46 47 4849 50

motor

angle

52 53 54 55 56 57 58 5960 61 62 63 64 65 6651

2^20 t

CLK

Figure 8.3 MicroPlyer microstep interpolation with rising STEP frequency.

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In Figure 8.3, the first STEP cycle is long enough to set the STST bit. This bit is cleared on the next STEP active edge. Then, the STEP frequency increases and after one cycle at the higher rate MicroPlyer increases the interpolated microstep rate. During the last cycle at the slower rate, MicroPlyer did not generate all 16 microsteps, so there is a small jump in motor angle between the first and second cycles at the higher rate.

8.5 Standstill current reduction

When a standstill event is detected, the motor current should be reduced to save energy and reduce heat dissipation in the power MOSFET stage. This is especially true at halfstep positions, which are a worst-case condition for the driver and motor because the full energy is consumed in one bridge and one motor coil.

Attention:

Stand still current reduction is required when operating near the thermal limits of the application. Refer the current and temperature limitations in chapter 17 as a guideline.

Hint

Implement a current reduction to 10% to 75% of the required run current for motor standstill. This saves more than 50% to more than 90% of energy. The actual level depends on the required holding force and on the required microstep precision during standstill. In standalone mode, a reduction to 50% current is possible using a configuration input.

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9 Current Setting

The internal 5V supply voltage available at the pin 5VOUT is used as a reference for the coil current regulation based on the sense resistor voltage measurement. The desired maximum motor current is set by selecting an appropriate value for the sense resistor. The sense resistor voltage range can be selected by the VSENSE bit in the DRVCONF register. The low sensitivity (high sense resistor voltage, VSENSE=0) brings best and most robust current regulation, while high sensitivity (low sense resistor voltage; VSENSE=1) reduces power dissipation in the sense resistor. This setting reduces the power dissipation in the sense resistor by nearly half.

After choosing the VSENSE setting and selecting the sense resistor, the currents to both coils are scaled by the 5-bit current scale parameter CS in the SGCSCONF register. The sense resistor value is chosen so that the maximum desired current (or slightly more) flows at the maximum current setting (CS = %11111).

Using the internal sine wave table, which has amplitude of 248, the RMS motor current can be calculated by:







  





















The momentary motor current is calculated as:















  













where:

CS is the effective current scale setting as set by the CS bits and modified by CoolStep. The effective value ranges from 0 to 31.

VFS is the sense resistor voltage at full scale, as selected by the VSENSE control bit (refer to the

electrical characteristics).

CURRENT

A/B

is the value set by the current setting in SPI mode or the internal sine table in STEP/DIR

mode.

Parameter

Description

Setting

Comment

0 … 31

Scaling factor: 1/32, 2/32, … 32/32

VSENSE

Allows control of the sense resistor voltage range or adaptation of one electronic module to different maximum motor currents.

325mV

173mV

Pay special attention concerning the thermal design and current limits imposed by it! Be sure to reduce the current to a value at or below the maximum standstill current limits as specified in chapter 17. This is important due to thermal restrictions for continuous current in a single bride. The worst case is standstill in a half step position where one bridge has 0 current and the

other bridge has RMS value * √2 current.

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9.1 Sense Resistors

Sense resistors should be carefully selected. The full motor current flows through the sense resistors. As they also see the switching spikes from the MOSFET bridges, a low-inductance type such as film or composition resistors is required to prevent spikes causing ringing. A low-inductance, low-resistance PCB layout is essential. Keep the high-current interconnections as short as possible as shown in Figure 9.1. A massive ground plane is best. Because the sense resistor inputs are susceptible to damage from negative overvoltages, an additional input protection resistor helps protect against a motor cable break or ringing on long motor cables.

SRA

SENSE

SRB

SENSE

10R to 47R

optional input

protection resistors

MOSFET

bridge

MOSFET

bridge

GND

TMC260 TMC261

Power supply GND

no common GND path not visible to TMC262

470nF

optional filter

capacitors

Figure 9.1 Sense resistor grounding and protection components

The sense resistor needs to be able to conduct the peak motor coil current, especially in motor standstill conditions, unless standby power is reduced. Under normal conditions, the sense resistor sees the motor coil current with a duty cycle well below 50%.

The peak sense resistor power dissipation is:







󰇡





  



󰇢







For high-current applications, power dissipation is halved by using the lower sense resistor voltage setting and the corresponding lower resistance value. In this case, any voltage drop in the PCB traces has a larger influence on the result. A compact power stage layout with massive ground plane is best to avoid parasitic resistance effects.

CHOICE OF R

SENSE

AND RESULTING MAX. MOTOR CURRENT FOR CS=31

SENSE

[Ω]

RMS current [A] VSENSE=0

RMS current [A] VSENSE=1

0.33

0.7

0.35

0.27

0.8

0.43

0.22

1.0

0.53

0.15

1.5

0.8

0.12

1.8 (above max. current)

1.0

0.10

2.2 (above max. current)

1.2

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10 Chopper Operation

The currents through both motor coils are controlled using choppers. The choppers work independently of each other. Figure 10.1 shows the three chopper phases:

SENSE

COIL

On Phase: current flows in direction of target current

SENSE

COIL

Fast Decay Phase: current flows in opposite direction of target current

SENSE

COIL

Slow Decay Phase: current re-circulation

Figure 10.1 Chopper phases.

Although the current could be regulated using only on phases and fast decay phases, insertion of the slow decay phase is important to reduce electrical losses and current ripple in the motor. The duration of the slow decay phase is specified in a control parameter and sets an upper limit on the chopper frequency. The current comparator can measure coil current during phases when the current flows through the sense resistor, but not during the slow decay phase, so the slow decay phase is terminated by a timer. The on phase is terminated by the comparator when the current through the coil reaches the target current. The fast decay phase may be terminated by either the comparator or another timer.

When the coil current is switched, spikes at the sense resistors occur due to charging and discharging parasitic capacitances. During this time, typically one or two microseconds, the current cannot be measured. Blanking is the time when the input to the comparator is masked to block these spikes.

There are two chopper modes available: a new high-performance chopper algorithm called spreadCycle and a proven constant off-time chopper mode. The constant off-time mode cycles through three phases: on, fast decay, and slow decay. The spreadCycle mode cycles through four phases: on, slow decay, fast decay, and a second slow decay.

Three parameters are used for controlling both chopper modes:

Parameter

Description

Setting

Comment

TOFF

Off time. This setting controls the duration of the slow decay time and limits the maximum chopper frequency. For most applications an off time within the range of 5µs to 20µs will fit. If the value is 0, the MOSFETs are all shut off and the motor can freewheel. If the value is 1 to 15, the number of system clock cycles in the slow decay phase is:





󰇛  󰇜 

The SD-Time is  







 



Chopper off.

1… 15

Off time setting. A setting in the range of 2-5 is recommended for SpreadCycle, higher values for classic chopper.

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Parameter

Description

Setting

Comment

TBL

Blanking time. This time needs to cover the switching event and the duration of the ringing on the sense resistor. For most low-current applications, a setting of 16 or 24 is good. For high-current applications, a setting of 36 or 54 may be required.

16 system clock cycles

24 system clock cycles

36 system clock cycles

54 system clock cycles

CHM

Chopper mode bit. SpreadCycle is recommended for most applications. 0

SpreadCycle mode

Constant off time mode

EN_PFD

Enable passive fast decay. Setting this bit, adds a passive fast decay phase of 512 clock cycles for each bridge following zero crossing of the motor current. The passive fast decay will dampen the energy of motor resonances at medium velocity.

Resonance dampening on.

10.1 spreadCycle Chopper

The SpreadCycle (patented) chopper algorithm is a precise and simple to use chopper mode which automatically determines the optimum length for the fast-decay phase. The SpreadCycle will provide superior microstepping quality even with default settings. Several parameters are available to optimize the chopper to the application.

Each chopper cycle is comprised of an on phase, a slow decay phase, a fast decay phase and a second slow decay phase (see Figure 10.3). The two slow decay phases and the two blank times per chopper cycle put an upper limit to the chopper frequency. The slow decay phases typically make up for about 30%-70% of the chopper cycle in standstill and are important for low motor and driver power dissipation.

Calculation of a starting value for the slow decay time TOFF:

EXAMPLE:

Target Chopper frequency: 25kHz. Assumption: Two slow decay cycles make up for 50% of overall chopper cycle time



















 

 

For the TOFF setting this means:

  󰇛



 



 󰇜

With 12 MHz clock this gives a setting of TOFF=3.0, i.e. 3. With 16 MHz clock this gives a setting of TOFF=4.25, i.e. 4 or 5.

The hysteresis start setting forces the driver to introduce a minimum amount of current ripple into the motor coils. The current ripple must be higher than the current ripple which is caused by resistive losses in the motor in order to give best microstepping results. This will allow the chopper to precisely regulate the current both for rising and for falling target current. The time required to introduce the current ripple into the motor coil also reduces the chopper frequency. Therefore, a higher hysteresis setting will lead to a lower chopper frequency. The motor inductance limits the ability of the chopper to follow a changing motor current. Further the duration of the on phase and the fast decay must be longer than the blanking time, because the current comparator is disabled during blanking.

It is easiest to find the best setting by starting from a low hysteresis setting (e.g. HSTRT=0, HEND=0) and increasing HSTRT, until the motor runs smoothly at low velocity settings. This can best be checked when measuring the motor current either with a current probe or by probing the sense

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resistor voltages (see Figure 10.2). Checking the sine wave shape near zero transition will show a small ledge between both half waves in case the hysteresis setting is too small. At medium velocities (i.e. 100 to 400 fullsteps per second), a too low hysteresis setting will lead to increased humming and vibration of the motor.

Figure 10.2 No ledges in current wave with sufficient hysteresis (magenta: current A, yellow & blue: sense resistor voltages A and B)

A too high hysteresis setting will lead to reduced chopper frequency and increased chopper noise but will not yield any benefit for the wave shape.

Quick Start

For detail tuning procedure see Application Note AN001 - Parameterization of SpreadCycle

As experiments show, the setting is quite independent of the motor, because higher current motors typically also have a lower coil resistance. Choosing a medium default value for the hysteresis (for example, effective HSTRT+HEND=10) normally fits most applications. The setting can be optimized by experimenting with the motor: A too low setting will result in reduced microstep accuracy, while a too high setting will lead to more chopper noise and motor power dissipation. When measuring the sense resistor voltage in motor standstill at a medium coil current with an oscilloscope, a too low setting shows a fast decay phase not longer than the blanking time. When the fast decay time becomes slightly longer than the blanking time, the setting is optimum. You can reduce the off-time setting, if this is hard to reach.

The hysteresis principle could in some cases lead to the chopper frequency becoming too low, for example when the coil resistance is high compared to the supply voltage. This is avoided by splitting the hysteresis setting into a start setting (HSTRT+HEND) and an end setting (HEND). An automatic hysteresis decrementer (HDEC) interpolates between these settings, by decrementing the hysteresis value stepwise each 16, 32, 48, or 64 system clock cycles. At the beginning of each chopper cycle, the hysteresis begins with a value which is the sum of the start and the end values (HSTRT+HEND), and decrements during the cycle, until either the chopper cycle ends or the hysteresis end value (HEND) is reached. This way, the chopper frequency is stabilized at high amplitudes and low supply voltage situations, if the frequency gets too low. This avoids the frequency reaching the audible range.

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target current

target current - hysteresis start

target current + hysteresis start

on sd fd sd

target current + hysteresis end

target current - hysteresis end

HDEC

Figure 10.3 spreadCycle chopper mode showing the coil current during a chopper cycle

Three parameters control spreadCycle mode:

Parameter

Description

Setting

Comment

HSTRT

Hysteresis start setting. Please remark, that this value is an offset to the hysteresis end value HEND.

0… 7

This setting adds to HEND. %000: 1 %100: 5 %001: 2 %101: 6 %010: 3 %110: 7 %011: 4 %111: 8

HEND

Hysteresis end setting. Sets the hysteresis end value after a number of decrements. Decrement interval time is controlled by HDEC. The sum HSTRT+HEND must be <16. At a current setting CS of max. 30 (amplitude reduced to 240), the sum is not limited.

0… 2

Negative HEND: -3… -1 %0000: -3 %0001: -2 %0010: -1

Zero HEND: 0 %0011: 0

4… 15

Positive HEND: 1… 12 %0100: 1 %1010: 7 1100: 9 %0101: 2 %1011: 8 1101: 10 %0110: 3 %1100: 9 1110: 11 %0111: 4 %1101: 10 %1000: 5 %1110: 11 %1001: 6 %1111: 12

HDEC

Hysteresis decrement setting. This setting determines the slope of the hysteresis during on time and during fast decay time. It sets the number of system clocks for each decrement.

0… 3

0: fast decrement

3: very slow decrement

%00: 16 %01: 32 %10: 48 %11: 64

EXAMPLE:

A hysteresis of 4 has been chosen. You might decide to not use hysteresis decrement. In this case set:

HEND=6 (sets an effective end value of 6-3=3) HSTRT=0 (sets minimum hysteresis, i.e. 1: 3+1=4)

In order to take advantage of the variable hysteresis, we can set most of the value to the HSTRT, i.e. 4, and the remaining 1 to hysteresis end. The resulting configuration register values are as follows:

HEND=0 (sets an effective end value of -3) HSTRT=6 (sets an effective start value of hysteresis end +7: 7-3=4)

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Hint

Highest motor velocities benefit from setting TOFF to 2 or 3 and a short TBL of 2 or 1.

10.2 Constant Off-Time Mode

The classic constant off-time chopper uses a fixed-time fast decay following each on phase. While the duration of the on phase is determined by the chopper comparator, the fast decay time needs to be fast enough for the driver to follow the falling slope of the sine wave, but it should not be so long that it causes excess motor current ripple and power dissipation. This can be tuned using an oscilloscope or evaluating motor smoothness at different velocities. A good starting value is a fast decay time setting similar to the slow decay time setting.

mean value = target current

target current + offset

sdfd

sdon

Figure 10.4 Constant off-time chopper with offset showing the coil current during two cycles

After tuning the fast decay time, the offset should be tuned for a smooth zero crossing. This is necessary because the fast decay phase makes the absolute value of the motor current lower than the target current (see Figure 10.5). If the zero offset is too low, the motor stands still for a short moment during current zero crossing. If it is set too high, it makes a larger microstep. Typically, a positive offset setting is required for smoothest operation.

Target current

Coil current

Target current

Coil current

Coil current does not have optimum shape Target current corrected for optimum shape of coil current

Figure 10.5 Zero crossing with correction using sine wave offset.

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Three parameters control constant off-time mode:

Parameter

Description

Setting

Comment

TFD (HSTART & HDEC0)

Fast decay time setting. With CHM=1, these bits control the portion of fast decay for each chopper cycle.

Slow decay only.

1… 15

Duration of fast decay phase.

OFFSET (HEND)

Sine wave offset. With CHM=1, these bits control the sine wave offset. A positive offset corrects for zero crossing error.

0…2

Negative offset: -3… -1

No offset: 0

4… 15

Positive offset: 1… 12

NCCFD (HDEC1)

Selects usage of the current comparator for termination of the fast decay cycle. If current comparator is enabled, it terminates the fast decay cycle in case the current reaches a higher negative value than the actual positive value.

Enable comparator termination of fast decay cycle.

End by time only.

10.2.1 Random Off Time

In the constant off-time chopper mode, both coil choppers run freely without synchronization. The frequency of each chopper mainly depends on the coil current and the motor coil inductance. The inductance varies with the microstep position. With some motors, a slightly audible beat can occur between the chopper frequencies when they are close together. This typically occurs at a few microstep positions within each quarter wave. This effect is usually not audible when compared to mechanical noise generated by ball bearings, etc. Another factor which can cause a similar effect is a poor layout of the sense resistor GND connections.

Hint

A common cause of motor noise is a bad PCB layout causing coupling of both sense resistor voltages. Noise caused by an insufficient PCB layout cannot be overcome by chopper settings.

To minimize the effect of a beat between both chopper frequencies, an internal random generator is provided. It modulates the slow decay time setting when switched on by the RNDTF bit. The RNDTF feature further spreads the chopper spectrum, reducing electromagnetic emission on single frequencies.

Parameter

Description

Setting

Comment

RNDTF

Enables a random off-time generator, which slightly modulates the off time t

OFF

using a

random polynomial.

Disable.

Random modulation enable.

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11 Power MOSFET Stage

The gate current for the power MOSFETs can be adapted to influence the slew rate at the coil outputs. The main features of the stage are:

- 5V gate drive voltage for low-side N-MOS transistors, 10V for high-side P-MOS transistors.

- The gate drivers protect the bridges actively against cross-conduction using an internal Q

protection that holds the MOSFETs safely off.

- Automatic break-before-make logic minimizes dead time and diode-conduction time.

- Integrated overcurrent protection detects a short of the motor wires and protects the

MOSFETs.

The low-side gate driver is supplied by the 5VOUT pin. The low-side driver supplies 0V to the MOSFET gate to close the MOSFET, and 5VOUT to open it. The high-side gate driver voltage is supplied by the VS and the VHS pin. VHS is more negative than VS and allows opening the VS referenced high-side MOSFET. The high-side driver supplies VS to the P channel MOSFET gate to close the MOSFET and VHS to open it. The effective low-side gate voltage is roughly 5V; the effective high-side gate voltage is roughly 8V.

Parameter

Description

Setting

Comment

SLPL

Low-side slope control. Controls the MOSFET gate driver current. Set to 0, 1 or 2. Slopes are fast to minimize package power dissipation.

0… 3

%00: Minimum. %01: Minimum. %10: Medium. %11: Maximum.

SLPH

High-side slope control. Controls the MOSFET gate driver current. For the TMC260 set identical to SLPL to match LS slope. For the TMC261 set to 0 or 1 for medium slope. Set to 2 to match low-side slope with SLPL=0 or

1. Set to 3 with SLPL=2.

0… 3

%00: Minimum. %01: Minimum+TC. %10: Medium+TC. %11: Maximum.

11.1 Break-Before-Make Logic

Each half-bridge has to be protected against cross-conduction during switching events. When switching off the low-side MOSFET, its gate first needs to be discharged before the high-side MOSFET is allowed to switch on. The same goes when switching off the high-side MOSFET and switching on the low-side MOSFET. The time for charging and discharging of the MOSFET gates depends on the MOSFET gate charge and the gate driver current set by SLPL and SLPH. The BBM (break-before-make) logic measures the gate voltage and automatically delays turning on the opposite bridge transistor until its counterpart is discharged. This way, the bridge will always switch with optimized timing independent of the slope setting.

11.2 ENN Input

The MOSFETs can be completely disabled in hardware by pulling the ENN input high. This allows the motor to free-wheel. An equivalent function can be performed in software by setting the parameter TOFF to zero. The hardware disable is available for allowing the motor to be hot plugged. For the TMC260, it can be used in overvoltage situations. The TMC260 can withstand voltages of up to 60V when the MOSFETs are disabled. If a hardware disable function is not needed, tie ENN low.

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12 Diagnostics and Protection

12.1 Short Protection

The TMC260C / TMC261C protects the MOSFET power stages against a short circuit or overload condition by monitoring the voltage drop in the high-side MOSFETs, as well as the voltage drop in sense resistor and low-side MOSFETs (Figure 12.1). A programmable short detection delay (shortdelay) allows adjusting the detector to work with different power stages and load conditions. Additionally, the short detection is protected against single events, e.g. caused by ESD discharges, by retrying three times before switching off the motor continuously. The low side short detector also provides for overcurrent detection. It needs to be explicitly enabled by programming.

Parameter

Description

Setting

Comment

SHRTSENS

The high-side overcurrent detector can be set to a higher sensitivity by setting this flag. This will allow detection of wrong cabling even with higher resistive motors.

0/1

0: Low sensitivity 1: High sensitivity

TS2G

Short detection delay for high-side and low side detectors. The short detection delay shall cover the bridge switching time. %01 will work for most applications. A higher delay makes detection less sensitive to capacitive load.

0/1

%00: 3.2µs. %01: 1.6µs. %10: 1.2µs. %11: 0.8µs.

DIS_S2G

Allows to disable short to VS protection.

0/1

Leave detection enabled for normal use (0).

EN_S2VS

Explicitly enable short to VS and overcurrent protection by setting this bit.

0/1

Enable detection for normal use (1).

LS short

detection

(S2VS)

No-short

area

HS short

detection

(S2G)

No-short

area

BMx

(coil output

voltage)

Internal high-side

driver enable

VS-V

S2G level

detection active

Short to GND monitor phase

Internal Error Flag

Short detected

short

delay

short delay

inactive

Short to GND detected

Driver disable

Output floating

S2VS level

Short to VS monitor phase

short delay

inactive

detection

active

inactive

Internal low-side

driver enable

Figure 12.1 Short detection timing

As the low-side short detection includes the sense resistor, it is sensitive to the actual sense resistor and provides a good precision of overcurrent detection. This way, it will safely cover most overcurrent conditions.

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Hint

Once a short condition is safely detected, the corresponding driver bridge (A or B) becomes switched off, and the s2ga or s2gb flag, respectively s2vsa or s2vsb becomes set. To restart the motor, disable and re-enable the driver.

Attention

Short protection cannot protect the system and the power stages for all possible short events, as a short event is rather undefined and a complex network of external components may be involved. Therefore, short circuits should basically be avoided.

12.2 Open-Load Detection

Interrupted cables are a common cause for systems failing, e.g. when connectors are not firmly plugged. The TMC260/TMC261 detect open load conditions by checking if it can reach the desired motor coil current. This way, also undervoltage conditions, high motor velocity settings or short and overtemperature conditions may cause triggering of the open load flag, and inform the user, that motor torque may suffer. In motor stand still, open load cannot be measured, as the coils might eventually have zero current.

Hint

Open load detection is provided for system debugging. Open load detection does not necessarily indicate a malfunction of the driver. To safely detect an interrupted coil connection, read out the open load flags at low or nominal motor velocity operation, only. However, the ola and olb flags have just informative character and do not cause any action of the driver. False indication may result with full- or halfstep operation. Use microstepping for a safe result.

The open-load detection status is indicated by two bits:

Status flag

Description

Range

Comment

SHORTA

The SHORT bits identify a short condition on coil A or coil B persisting for multiple chopper cycles. The bits are cleared when the MOSFETs are disabled.

Detailed warning for high-side or low-side FETs is available in S2VSA and S2VSB (low-side short detector) and S2GA and S2GB (high-side short detector)

0 / 1

0: No short detected 1: Short detected

SHORTB

S2VSA

S2VSB

S2GA

S2GB

Status flag

Description

Range

Comment

OLA

These bits indicate an open-load condition on coil A and coil B. The flags become set, if no chopper event has happened during the last period with constant coil polarity. The flag is not updated with too low actual coil current below 1/16 of maximum setting. It is a pure indicator. No action is taken depending on these flags.

0 / 1

0: No open-load

detected

1: Open-load

detected

OLB

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12.3 Temperature Sensors

The drivers integrate a four-level temperature sensor (100°C pre-warning, 120°C overtemperature release and selectable 136°C / 150°C thermal shutdown) for diagnostics and for protection of the IC and the integrated MOSFETs as well as for adjacent components against excess heat. Choose the overtemperature level to safely cover error conditions like missing heat convection. Heat is mainly generated by the power MOSFETs, and, at increased voltage, by the internal voltage regulators. For many applications, already the overtemperature pre-warning will indicate an abnormal operation situation and can be used to initiate user warning or power reduction measures like motor current reduction. The thermal shutdown is just an emergency measure and temperature rising to the shutdown level should be prevented by design.

Hint for -C type, only

After triggering the overtemperature sensor (ot flag), the driver remains switched off until the system temperature falls below the overtemperature release level (120°C) to avoid continuous heating to the shutdown level. Cool down typically needs a few 100ms to 1 second.

The high-side P-channel gate drivers have a temperature dependency which can be compensated to some extent by increasing the gate driver current when the warning temperature threshold is reached. The chip automatically corrects for the temperature dependency above the warning temperature when the temperature-compensated modes of SLPH is used. In these modes, the gate driver current is increased by one step when the temperature warning threshold is reached.

12.4 Undervoltage Detection

The undervoltage detector monitors both the internal logic supply voltage and the supply voltage. It prevents operation of the chip when the MOSFETs cannot be guaranteed to operate properly because the gate drive voltage is too low. It also initializes the chip at power up.

In undervoltage conditions, the logic control block becomes reset and the driver is disabled. All MOSFETs are switched off. All internal registers are reset to zero. Software should additionally monitor the supply voltage to detect an undervoltage condition. If software cannot measure the supply voltage, an undervoltage condition can be detected by reading out the SE current value. Following a reset due to undervoltage occurs, the CS parameter is cleared, which is reflected in an SE status of 0 in the read response.

Status

Description

Range

Comment

OTPW

Overtemperature warning. This bit indicates whether the warning threshold is reached. Software can react to this setting by reducing current.

0 / 1

1: temperature

prewarning level

reached

Overtemperature shutdown. This bit indicates whether the shutdown threshold has been reached and the driver has been disabled.

0 / 1

1: driver shut down

due to over-

temperature

OTSENS (-C type only)

Program overtemperature threshold to a reduced level to give better protection for the external power stage and other components. The driver reenables when the temperature falls below 120°C.

0 / 1

0: 150°C 1: 136°C

Status

Description

Range

Comment

EN_PFD (-C type only)

Set this bit to allow operation with a 5V only supply. This bit additionally controls resonance dampening of the motor.

0 / 1

Undervoltage level 0: <7V 1: <4.5V

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Time

Device in reset: all

registers cleared to 0

Reset

ca. 100µs ca. 100µs

Figure 12.2 Undervoltage reset timing

Note

Be sure to operate the IC significantly above the undervoltage threshold to ensure reliable operation! Check for SE reading back as zero to detect an undervoltage event.

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13 Power Supply Sequencing

The TMC260/TMC261 generate their own 5V supply for all internal operations. The internal reset of the chip is derived from the supply voltage regulator in order to ensure a clean start-up of the device after power up. During start up, the SPI unit is in reset and cannot be addressed. All registers become cleared.

VCC_IO limits the voltage allowable on the inputs and outputs and is used for driving the outputs. It is included in undervoltage detection and reset (C-type, only). Therefore, the startup sequence of the VCC_IO power supply with respect to VS is not important. VCC_IO may start up before or after VS.

14 System Clock

The system clock is the timing reference for all functions. The internal system clock frequency for all operations is nominally 15MHz. An external clock of 8MHz to 20MHz can be supplied for more exact timing, especially when using CoolStep and StallGuard2.

USING THE INTERNAL CLOCK

To use the on-chip oscillator of the TMC260 / TMC261, tie CLK to GND near the chip. The actual on-chip oscillator clock frequency can be determined by measuring the delay time between the last step and assertion of the STST (standstill) status bit, which is 220 clocks. There is some delay in reading the STST bit through the SPI interface, but it is easily possible to measure the oscillator frequency within 1%. Chopper timing parameters can then be corrected using this measurement, because the oscillator is relatively stable over a wide range of environmental temperatures.

Hint

In case well defined precise motor chopper operation are desired, it is supposed to work with an external clock source.

USING EXTERNAL CLOCK

An external clock frequency of up to 20MHz can be supplied. It is recommended to use an external clock frequency between 10MHz and 16MHz for best performance. Pay attention to using a near 50% duty-cycle. The external clock is enabled and the on-chip oscillator is disabled with the first logic high driven on the CLK input.

Attention: Never leave the external clock input floating. It is not allowed to remain within the transition region (between valid low and high levels), as spurious clock signals might lead to short impulses and can corrupt internal logic state. Provide an external pull-down resistor, in case the driver pin (i.e. microcontroller output) does not provide a safe level directly after power up. If the external clock is suspended or disabled after the internal oscillator has been disabled, the chip will not operate. Be careful to switch off the power MOSFETs (by driving the ENN input high or setting the TOFF parameter to 0) before switching off the clock, because otherwise the chopper would stop and the motor current level could rise uncontrolled. If the short to GND detection is enabled, it stays active even without clock. The -C types provides a clock failover option to switch back to internal clock, in case of the external clock failing. The function is coupled to enabling short to VS protection (EN_S2VS).

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Time

Device in reset: all

registers cleared to 0

VCC_IO

max. VCC_IO

Device in reset: all

registers cleared to 0

Defined clock, no intermediate levels allowed

CLK must be

low, while

VCC_IO is

below V

INHI

3.3V/5V

Operation, CLK is not allowed to have undefined

levels between V

INLO

and V

INHI

and timing must

satisfy T

CLK

(min)

CLK

Figure 14.1 Start-up requirements of CLK input

14.1 Frequency Selection

A higher frequency allows faster step rates, faster SPI operation, and higher chopper frequencies. On the other hand, it may cause more electromagnetic emission and more power dissipation in the digital logic. Generally, a system clock frequency of 10MHz to 16MHz is best for most applications, unless the motor is to operate at the highest velocities. If the application can tolerate reduced motor velocity and increased chopper noise, a clock frequency of 4MHz to 10MHz should be considered.

CLK frequency

Comment

internal

13-16MHz, typical. Tie clock input firmly to GND. See electrical characteristics for limits. The internal clock is sufficient, unless a good reproducibility of StallGuard values is desired.

4-10 MHz

Lower range sufficient for higher inductance motors

10-16 MHz

Recommended for best results

16-20 MHz

Option in case a lower frequency is not available Ensure 40-60% duty cycle

Status

Description

Range

Comment

EN_S2VS (-C type only)

Set this bit to enable protection against a failing external CLK source. If set, the IC switches back to external clock after 32 to 48 internal clock cycles. At the same time, this bit controls the higher side short detector sensitivity

0 / 1

Undervoltage level 0: Stopping clock will

stop the IC.

1: CLK fail safe

protection

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15 Compatibility to non-C-type

The TMC260C / TMC261C are downward compatible to the non-C-types. They are designed for compatibility to existing applications, while offering several enhancements and options for new designs.

ENHANCEMENTS IN C-TYPE

• More silent chopper operation, silent motor at low motor velocity.

• VCC_IO is monitored by internal reset circuitry to ensure clean power-up and power-down.

• Overtemperature shutdown has added hysteresis. After exceeding the temperature threshold, the

driver stage remains off, until temperature falls below the 120°C pre-warning threshold.

• Reduced power dissipation of internal circuitry, leading to lower heat-up.

• CMOS input levels are increased with 5V VCC_IO level to increase noise rejection.

• Reduced filtering time for STEP & DIR inputs to reduce the risk of missed step pulses.

OPTIONAL ENHANCEMENTS IN C-TYPE (ENABLE VIA CONFIGURATION BITS)

• Clock fail-safe option. In case the external clock fails, the IC defaults back to internal clock. This

avoids damage to motor and driver stage. (Enable: EN_S2VS, together with short protection)

• Low-Side short detection (Short to VS) for improved robustness in case of mis-wiring or

overcurrent, e.g. due to wrongly attached motor. (Enable: EN_S2VS)

• Optional higher sensitivity high-side protection for improved protection. (Enable: SHRTSENS)

• Optional lower overtemperature threshold of 136°C for more sensitive protection of the power

driver. Enable: OTSENSE

• Option to work down to 5V supply voltage and to add resonance dampening. (Enable: EN_PFD)

The additional settings for C-types are highlighted in this document using green background.

The major differences to be considered when migrating an existing application from the TMC260 / TMC261 to TMC260C / TMC261C, are summarized in the following table:

Item

Change in C-type

Impact

More silent chopper in Ctype

Internal noise sources have been reduced. Noise caused by internal wiring voltage drop makes up for up to 10mV for non-C-devices. This reflects in a slightly lower sense input threshold voltage.

More silent motor, especially with low velocity. C-type effective motor current about 2-3% higher.

Undervoltage monitoring of VCC_IO

IO voltage VCC_IO is monitored by the internal reset circuitry. The device becomes reset upon VCC_IO undervoltage.

Increased VCC_IO supply current (50µA), device resets upon VCC_IO undervoltage.

Hysteresis for overtemperature detector

Following overtemperature detection at 136°C or 150°C, the driver stage remains switched off until the IC cools down below 120°C.

Longer shutdown time upon overtemperature detection, safe detection by interface.

Input levels depend on VCC_IO voltage

Non-C-type input level detectors are supplied by internal 5V supply, leading to fixed 0.8V and 2.4V levels. C-types use VCC_IO supplied CMOS SchmittTrigger inputs instead.

Higher positive logic level for 5V VCC_IO supply. No change with 3.3V VCC_IO supply. Check levels in 5V systems.

Spike filtering time on STEP/DIR input

The filtering has been improved, while reducing the filtering time in order to reduce the risk of missing short step pulses.

Potential impact in systems with high noise level on STEP & DIR input pins.

CLK input filter

C-type provides better filtering against short pulses (10ns typ.).

More robust against reflections on CLK. Check timing in case of SPI rate at ½ f

CLK

Invert CLK signal if required.

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16 Layout Considerations

The PCB layout is critical to good performance, because the environment includes both highsensitivity analog signals and high-current motor drive signals.

16.1 Sense Resistors

The sense resistors are susceptible to ground differences and ground ripple voltage, as the microstep current steps result in voltages down to 0.5mV. No current other than the sense resistor currents should flow through their connections to ground. Place the sense resistors close to chip with one or more vias to the ground plane for each sense resistor.

The sense resistor layout is also sensitive to coupling between the axes. The two sense resistors should not share a common ground connection trace or vias, because PCB traces have some resistance.

16.2 Power MOSFET Outputs

The OA and OB dual pin outputs on the TMC260 and TMC261 are directly connected electrically and thermally to the drain of the MOSFETs of the power stage. A symmetrical, thermally optimized layout is required to ensure proper heat dissipation of all MOSFETs into the PCB. Use thick traces and areas for vertical heat transfer into the GND plane and enough vias for the motor outputs.

The printed circuit board should have a solid ground plane spreading heat into the board and providing for a stable GND reference. All signals of the TMC260 and TMC261 are referenced to GND. Directly connect all GND pins to a common ground area.

The switching motor coil outputs have a high dV/dt, so stray capacitive coupling into high-impedance signals can occur, if the motor traces are parallel to other traces over long distances.

16.3 Power Supply Pins

Both, the VSA and VSB pins, as well as the BRA and BRB pins conduct the full motor current for a limited amount of time during each chopper cycle. Due to the resistance of bond wires connected to these pins, the pins heat up. Therefore, it is essential for current capability above 2A RMS to use a wide PCB trace for cooling and to avoid additional heat up of the pins caused by PCB trace resistance. This is simplified by also contacting the N.C. pins located next to VSA and VSB to the supply voltage. Failure to do so might affect reliability; despite heat-up of bond wires might not be visible with a thermal camera.

16.4 Power Filtering

The 470nF ceramic filtering capacitor on 5VOUT should be placed as close as possible to the 5VOUT pin, with its GND return going directly to the nearest GND pin. Use as short and as thick connections as possible. A 100nF filtering capacitor should be placed as close as possible from the VS pin to the

ground plane. The motor supply pins, VSA and VSB, should be decoupled with an electrolytic (>47 μF

is recommended) capacitor and a ceramic capacitor, placed close to the device. Also place minimum 100nF capacitor for VCC_IO close to the supply pin.

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16.5 Layout Example

EXAMPLE FOR UP TO 1.4A RMS

Here, an example for a layout with small board size (≈20cm²) is shown.

top layer (assembly side)

inner layer inner layer

bottom layer (solder side)

Figure 16.1 Layout example for TMC260 and TMC261

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17 Absolute Maximum Ratings

The maximum ratings may not be exceeded under any circumstances. Operating the circuit at or near more than one maximum rating at a time for extended periods shall be avoided by application design.

Parameter

Symbol

Min

Max

Unit

Supply voltage (TMC261, TMC261A, TMC261C)

-0.5

Supply voltage (TMC260, TMC260A, TMC260C)

-0.5

Logic supply voltage

VCC

-0.5

6.0

I/O supply voltage

VIO

-0.5

6.0

Logic input voltage

-0.5

VIO

+0.5

Analog input voltage

VIA

-0.5

VCC+0.5

Relative high-side gate driver voltage (VVM – VHS)

HSVM

-0.5

Maximum current to/from digital pins and analog low voltage I/Os

IIO +/-10

Non-destructive short time peak current into input/output pins

IIO 500

Bridge output peak current (10µs pulse)

IOP +/-7

Output current, continuous (one bridge active, or 0.71 x current with both bridges active)

TA ≤ 50°C

IOC

2000

TA ≤ 85°C

1500

TA ≤ 105°C

1100

TA ≤ 125°C

800

5V regulator output current

5VOUT

5V regulator peak power dissipation (VVM-5V) * I

5VOUT

Junction temperature

-50

150

°C

Storage temperature

STG

-55

150

°C

ESD-Protection (Human body model, HBM), in application

ESDAP

ESD-Protection (Human body model, HBM), device handling

ESDDH

300

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18 Electrical Characteristics

18.1 Operational Range

Parameter

Symbol

Min

Max

Unit

Junction temperature

-40

125

°C

Supply voltage TMC261C

VVS 5 59

Supply voltage TMC260C

VVS 5 39

I/O supply voltage

VIO

3.00

5.25

18.2 DC and AC Specifications

DC characteristics contain the spread of values guaranteed within the specified supply voltage range unless otherwise specified. Typical values represent the average value of all parts measured at +25°C. Temperature variation also causes some values to stray. A device with typical values will not leave Min/Max range within the full temperature range.

Power Supply Current

DC Characteristics

VVS = 24.0V

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Supply current, operating

IVS

CLK

=16MHz, 40kHz

chopper

Supply current, MOSFETs off

IVS

CLK

=12MHz

Supply current, MOSFETs off, dependency on CLK frequency

IVS

CLK

variable

additional to I

VS0

0.1 mA/

MHz

Static supply current

VS0

CLK

=0Hz, digital inputs

at +5V or GND

3.5 5 mA

Part of supply current NOT consumed from 5V supply

VSHV

MOSFETs off

1.2 mA

IO supply current

VIO

No load on outputs, inputs at VIO or GND

100

µA

High-Side Voltage Regulator

DC-Characteristics VVS = 24.0V

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Output voltage (VVS – VHS)

HSVS

OUT

= 0mA

TJ = 25°C

9.3

10.0

10.8

Lower voltage for VHS regulator to activate

VVS

VS rising, first time VHS goes up from 0V

12.5

Output resistance

VHS

Static load



Linear Regulator

DC Characteristics

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Output voltage

5VOUT

= 10mA

TJ = 25°C

4.75

5.0

5.25

Output resistance

5VOUT

Static load



Deviation of output voltage over the full temperature range

5VOUT(DEV)

5VOUT

= 10mA

TJ = full range

0 60

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Internal MOSFETs TMC260C

DC Characteristics

VVS = V

VSX

≥ 12.0V, V

BRX

= 0V

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

N-channel MOSFET resistance

ONN

TJ = 25°C

100

150

mΩ

P-channel MOSFET resistance

ONP

TJ = 25°C

160

210

mΩ

N-channel MOSFET resistance

ONN

TJ = 150°C

164 mΩ

P-channel MOSFET resistance

ONP

TJ = 150°C

262 mΩ

Internal MOSFETs TMC261C

DC Characteristics

VVS = V

VSX

≥ 12.0V, V

BRX

= 0V

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

N-channel MOSFET resistance

ONN

TJ = 25°C

140

mΩ

P-channel MOSFET resistance

ONP

TJ = 25°C

170

225

mΩ

N-channel MOSFET resistance

ONN

TJ = 150°C

150 mΩ

P-channel MOSFET resistance

ONP

TJ = 150°C

280 mΩ

Clock Oscillator and CLK Input

Timing Characteristics Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Clock oscillator frequency

CLKOSC

tJ=-50°C

10.0

13.5

MHz

Clock oscillator frequency

CLKOSC

tJ=50°C

10.8

14.3

17.5

MHz

Clock oscillator frequency

CLKOSC

tJ=150°C

14.5

18.0

MHz

External clock frequency (operating)

CLK

Typ. at 40%/60% dutycycle, Max at 50% dutycycle

10-16

MHz External clock high / low level time

CLK

External clock first pulse to trigger switching to external CLK

CLKH

CLKL

External clock transition time

TRCLK

INLO

to V

INHI

or back

External clock timeout detection in cycles of internal f

CLKOSC

timeout

External clock stuck at low or high

32 48

cycles

CLKOSC

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Detector Levels

DC Characteristics

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

VVS undervoltage threshold high

VUV

EN_PFD=0

6.5 7 7.5

VVS undervoltage threshold low

VUV

EN_PFD=1

3.25

3.8

4.25

VCC_IO

undervoltage threshold

for RESET

UV_VIO

VCC_IO

rising (delay

typ. 10µs)

2.1

2.55

3.0

VCC_IO

undervoltage detector

hysteresis

UV_VIOHYS

0.3 V

Short to GND detector threshold (high setting) (VVS - V

BMx

)

BMS2G

1.2

1.7

2.3

Short to GND detector threshold (sensitive setting) (VVS - V

BMx

)

BMS2G

0.7

1.0

1.3

V Short to VS detector threshold (V

BMx

)

BMS2VS

1.3

1.5

1.8

Short to GND detector delay (low-side gate off detected to short detection)

S2G

TS2G=00

2.0

3.2

4.5

µs

TS2G=10

1.6 µs

TS2G=01

1.2 µs

TS2G=11

0.8 µs

Overtemperature warning

OTPW

100

115

°C

Overtemperature release

OTR

Temperature falling

120 °C

Overtemperature shutdown lo

OTL

Temperature rising

136 °C

Overtemperature shutdown hi

OTH

Temperature rising

135

150

170

°C

Sense Resistor Voltage Levels

DC Characteristics

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Sense input peak threshold voltage (low sensitivity)

SRTRIPL

VSENSE=0 Cx=248; Hyst.=0

310

323

340

Sense input peak threshold voltage (high sensitivity)

SRTRIPH

VSENSE=1 Cx=248; Hyst.=0

155

173

190

Digital Logic Levels

DC Characteristics

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Input voltage low level a)

INLO

-0.3

0.3 V

VIO

Input voltage high level a)

INHI

0.7 V

VIO

+0.3

Output voltage low level

OUTLO

= 2mA

0.2

Output voltage high level

OUTHI

= -2mA

VIO

-0.2

Input leakage current

ILEAK

-10 10

µA

Digital pin capacitance

3.5 pF

Notes:

a) Digital inputs left within or near the transition region substantially increase power supply

current by drawing power from the internal 5V regulator. Make sure that digital inputs become driven near to 0V and up to the VIO I/O voltage. There are no on-chip pull-up or pulldown resistors on inputs.

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18.3 Thermal Characteristics

Please refer to TMC2660-EVAL for a sample layout. The TMC2660 shares the same structure and footprint as the TMC260 / TMC261

Parameter

Symbol

Conditions

Typ

Unit

Thermal resistance bridge transistor junction to ambient, soldered to 4 layer 20cm² PCB (or 20cm² size per driver IC for multiple driver board)

THA14

one bridge chopping, fixed polarity

K/W

THA24

two bridges chopping, fixed polarity

K/W

THA44

Motor running

K/W

Thermal resistance bridge transistor junction to ambient, soldered to 4 layer 50cm² PCB

THA44a

Motor running

K/W

When operating the device near its current limits, ensure a good thermal design of the PCB layout to avoid overheating of the integrated power MOSFETs. Due to its multichip-construction with individual heat transfer for each MOSFET of the power stage to the PCB using two pins, thermal characteristics depend on the layout symmetry. The actual thermal resistance also depends on the duty cycle and the die temperature. Use the thermal characteristics and the sample layout as a guideline for your own board layout. In case, the driver is to be operated at high current levels, special care should be taken to spread the heat generated by the driver power bridges efficiently within the PCB.

The worst-case thermal resistance occurs during motor stand still with the motor stopped in a half step position (one coil full current, other coil 0 current), as well as cyclic in slow motion below 4FS/s. Assume roughly 80°C/W, when there is only one bridge chopping. This is the worst-case scenario for heat-up. In stand still, with two bridges chopping at identical current (fullstep position), thermal resistance is reduced, because the power dissipation is distributed to more MOSFETs. Reduce stand still current to 68% or less, to compensate for both stand still scenarios. When the motor is running, calculate thermal resistance for the complete chip (all 8 MOSFETs working).

The MOSFET and bond wire temperature should not exceed 150°C, despite temperatures up to 200°C will not immediately destroy the devices. But the package plastics will apply strain onto the bond wires, so that cyclic, repetitive exposure to temperatures above 150°C may damage the electrical contacts and increase contact resistance and eventually lead to contract break. As the MOSFET temperatures cannot be monitored within the system, it is a good practice to react to the temperature pre-warning by reducing motor current, rather than relying on the overtemperature switch off.

Check MOSFET temperature under worst case conditions not to exceed 150°C using a thermal camera to validate your layout. Please carefully check your layout against the sample layout or the layout of the TMC2660-Evaluation board on the TRINAMIC website in order to ensure proper cooling of the IC!

Figure 18.1 One TMC260 operating at 1.4A RMS (2A peak), other TMC260 devices at 1.1A RMS

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19 Package Mechanical Data

19.1 Dimensional Drawings

Attention: Drawings not to scale.

Parameter

Ref

Min

Nom

Max

Size over pins (X and Y)

A 12

Body size (X and Y)

C 10

Pin length

D 1

Total thickness

1.6

Lead frame thickness

0.09 0.2

Stand off

0.05

0.10

0.15

Pin width

0.30

0.45

Flat lead length

0.45

0.75

Pitch K

0.8

Coplanarity

ccc

0.08

19.2 Package Code

Device

Package

Temperature range

Code/marking

TMC260C

PQFP44 (RoHS)

-40° to +125°C

TMC260C-PA

TMC261C

PQFP44 (RoHS)

-40° to +125°C

TMC261C-PA

Figure 19.1 Dimensional drawings (PQFP44)

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20 Disclaimer

TRINAMIC Motion Control GmbH & Co. KG does not authorize or warrant any of its products for use in life support systems, without the specific written consent of TRINAMIC Motion Control GmbH & Co. KG. Life support systems are equipment intended to support or sustain life, and whose failure to perform, when properly used in accordance with instructions provided, can be reasonably expected to result in personal injury or death.

Information given in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed for the consequences of its use nor for any infringement of patents or other rights of third parties which may result from its use.

Specifications are subject to change without notice.

All trademarks used are property of their respective owners.

21 ESD Sensitive Device

The TMC260 and the 261 are ESD-sensitive CMOS devices and sensitive to electrostatic discharge, due to discrete MOSFETs integrated into the package. Take special care to use adequate grounding of personnel and machines in manual handling. After soldering the devices to the board, ESD requirements are more relaxed. Failure to do so can result in defects or decreased reliability.

Note: In a modern SMD manufacturing process, ESD voltages well below 100V are standard. A major source for ESD is hot-plugging the motor during operation. As the power MOSFETs are discrete devices, the device in fact is very rugged concerning any ESD event on the motor outputs. All other connections are typically protected due to external circuitry on the PCB.

22 Designed for Sustainability

Sustainable growth is one of the most important and urgent challenges today. We at Trinamic try to contribute by designing highly efficient IC products, to minimize energy consumption, ensure best customer experience and long-term satisfaction by smooth and silent run, while minimizing the demand for external resources, e.g. for power supply, cooling infrastructure, reduced motor size and magnet material by intelligent control interfaces and advanced algorithms.

Please help and design efficient and durable products made for a sustainable world.

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23 Table of Figures

Figure 1.1 applications block diagram ............................................................................................................................ 4

Figure 2.1 TMC260/261 pin assignments (top view) ................................................................................................... 6

Figure 3.1 TMC260 and TMC261 block diagram ............................................................................................................ 8

Figure 3 Standalone configuration .................................................................................................................................. 9

Figure 4.1 StallGuard2 load measurement SG as a function of load .................................................................. 10

Figure 4.2 Linear interpolation for optimizing SGT with changes in velocity. ................................................. 11

Figure 6.1 Energy efficiency example with CoolStep ............................................................................................... 13

Figure 5.2 CoolStep adapts motor current to the load. .......................................................................................... 14

Figure 6.1 SPI Timing ........................................................................................................................................................ 16

Figure 6.2 Interfaces to a TMC429 motion controller chip and a TMC260 or TMC261 motor driver .......... 17

Figure 7.1 STEP and DIR timing. .................................................................................................................................... 28

Figure 7.2 Internal microstep table showing the first quarter of the sine wave. .......................................... 29

Figure 7.3 MicroPlyer microstep interpolation with rising STEP frequency. ..................................................... 30

Figure 8.1 Sense resistor grounding and protection components ...................................................................... 33

Figure 9.1 Chopper phases. ............................................................................................................................................. 34

Figure 9.2 No ledges in current wave with sufficient hysteresis (magenta: current A, yellow & blue:

sense resistor voltages A and B) ................................................................................................................................... 36

Figure 9.3 spreadCycle chopper mode showing the coil current during a chopper cycle ........................... 37

Figure 9.4 Constant off-time chopper with offset showing the coil current during two cycles ................ 38

Figure 9.5 Zero crossing with correction using sine wave offset. ....................................................................... 38

Figure 12.1 Short detection timing ................................................................................................................................ 41

Figure 11.2 Undervoltage reset timing ......................................................................................................................... 44

Figure 13.1 Start-up requirements of CLK input ........................................................................................................ 46

Figure 14.1 Layout example for TMC260 and TMC261 .............................................................................................. 49

Figure 16.1 One TMC260 operating at 1.4A RMS (2A peak), other TMC260 devices at 1.1A RMS ................ 54

Figure 17.1 Dimensional drawings (PQFP44) .............................................................................................................. 55

24 Revision History

Version

Date

Author

BD – Bernhard Dwersteg

Description

1.00

2020-JUL-07

New version for -C types. Non-C-type information only for reference

1.01

2020-AUG-11

Correction of pin list

25 References

[TMC262] TMC262 Datasheet (please refer to our homepage http://www.trinamic.com) [TMC429+TMC26x-EVAL] TMC429+TMC26x-EVAL Evaluation Board Manual

TRINAMIC TMC260C-PA Datasheet

Specifications and Main Features

Frequently Asked Questions

User Manual