Philips TDA5341 Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA5341

Brushless DC motor and VCM drive circuit with speed control

Product speciﬁcation File under Integrated Circuits, IC11

1997 Jul 10

Philips Semiconductors Product speciﬁcation

Brushless DC motor and VCM drive circuit with speed control

FEATURES

• Full-wave commutation (using push-pull output stages) without position sensors

• Built-in start-up circuitry

• Three push-pull MOS outputs:

– 1 A output current – Low voltage drop – Built-in current limiter

• Thermal protection

• General purpose operational amplifier

• Reset generator

• Motor brake facility

• Actuator driver (H-bridge current-controlled)

• Power-down detector

• Automatic park and brake procedure

• Adjustable park voltage

• Sleep mode

• Speed control with Frequency-Locked Loop (FLL)

• Serial port

• Friction reduction prior to spin-up.

APPLICATIONS

• Hard Disk Drive (HDD).

GENERAL DESCRIPTION

The TDA5341 is a BiCMOS integrated circuit used to drive brushless DC motors in full-wave mode. The device senses the rotor position using an EMF sensing technique and is ideally suited as a drive circuit for a hard disk drive motor.

The TDA5341 also includes a Voice Coil Motor driver (VCM), reset and park facilities and an accurate speed regulator. In addition, a serial port facilitates the control of the device.

TDA5341

QUICK REFERENCE DATA

Measured over full voltage and temperature range.

SYMBOL PARAMETER MIN. TYP. MAX. UNIT

oMOT

DS(MOT)

oACT

DS(ACT)

ORDERING INFORMATION

TYPE

NUMBER

TDA5341G LQFP64

general supply voltage for logic and power 4.5 5.0 5.25 V motor output current 1.3 1.6 1.9 A motor output resistance − 1.1 1.56 Ω actuator output current 0.7 1.1 1.4 A actuator output resistance − 2.0 2.5 Ω

PACKAGE

NAME DESCRIPTION VERSION

plastic low proﬁle quad ﬂat package; 64 leads; body 10 × 10 × 1.4 mm

SOT314-2

1997 Jul 10 2

Philips Semiconductors Product speciﬁcation

Brushless DC motor and VCM drive circuit with speed control

BLOCK DIAGRAM

handbook, full pagewidth

CAPCP

FREDENA

TESTIN

CAPCDM

CAPCDS

CAPTI

CAPST

BRAKE

FMOT

CLOCK

DATA

ENABLE

RESET

ROSC

DPULSE

RETRACT

CMIN1

CMIN2

ref

GAINSEL

CAPXA

18 19

10 58

39 38 42 57

33 34 36

CAPXB

UPPER VOLTAGE

THERMAL

SWITCH

ADAPTIVE

COMMUTATION

DELAY

TIMING

OSCILLATOR

START

OSCILLATOR

BRAKE

CONTROLLER

POLES

DIVIDER

SERIAL

PORT

PROGRAMMING

FREQUENCY

DIVIDER

VCM

PREAMPLIFIER

50 14 55 31 49 17

CAPYA

CONVERTER

CAPYB

COMMUTATION

AND OUTPUT DRIVING

LOGIC

brake

BAND GAP 1

sleep

fill

DIGITAL

FREQUENCY

COMPARATOR

park

CNTRL

CAPCPC

222463625961

CONTROL

AMPLIFIER

POWER 1

POWER 2

POWER 3

COMPARATORS

BAND GAP 2

UNDER-VOLTAGE

DETECTOR

BRAKE

AFTER PARK

CHARGE

PUMP

SENSE

AMPLIFIER

VCM

H-BRIDGE

CURRENT

LIMIT

CONTROL

TDA5341

25 64 40 16 41

ILIM

TDA5341

PRESET

MOT1

MOT2

MOT3

MOT0

CLAMP1

CLAMP2

RESETOUT

UVDIN1

UVDIN2

BRAKEDELAY

AMPOUT

AMPIN−

AMPIN+

FILTER

SENSEOUT

SENSEIN+

SENSEIN−

VCM+

VCM−

FB1

FB2

EEDVEE1VEE2VEE3VEE4VEEVDD1VDD2VDD3VDDVDDD

Fig.1 Block diagram.

1997 Jul 10 3

MGE817

Philips Semiconductors Product speciﬁcation

Brushless DC motor and VCM drive circuit

TDA5341

with speed control

PINNING

SYMBOL PIN DESCRIPTION

CAPST 1 external capacitor for starting oscillator CAPTI 2 external capacitor for timer circuit CLAMP1 3 external capacitor used to park the heads; must be externally connected to CLAMP2 AMPOUT 4 uncommitted operational ampliﬁer output AMPIN− 5 uncommitted operational ampliﬁer invert input AMPIN+ 6 uncommitted operational ampliﬁer direct input MOT0 7 motor centre tap input MOT2 8 motor driver output 2 FREDENA 9 friction reduction mode enable input (active HIGH) FG 10 frequency generator (tacho) output BRAKE 11 brake input command (active LOW) TESTIN 12 test input for power output switch-off (active HIGH) TP1 13 test purpose 1 (should be left open-circuit) V

EE1

GAINSEL 15 VCM gain adjustment input (switch ON when GAINSEL is LOW) V

CAPCDM 18 external capacitor for adaptive commutation delay (master) CAPCDS 19 external capacitor for adaptive commutation delay (slave) PRESET 20 set the motor drivers into a ﬁxed state: MOT1 = F (ﬂoating), MOT2 = L, MOT3 = H MOT3 21 motor driver output 3 CAPCPC 22 frequency compensation of the current control ILIM 23 current limit control input CNTRL 24 motor control V

DD1

CLAMP2 26 external capacitor used to park the heads; must be externally connected to CLAMP1 CAPCP 27 external capacitor for the charge pump output FB1 28 output of the VCM preampliﬁers FB2 29 switchable output of the VCM preampliﬁer RETRACT 30 park input command (active LOW) V

EE3

FILTER 32 charge pump output to be connected to an external ﬁlter V

CMIN1

CMIN2

DPULSE 35 data pulse input of the frequency comparator of the speed control V

ref

VCM+ 37 positive output of the VCM ampliﬁer DATA 38 input data of the serial port (active HIGH) CLOCK 39 clock input signal to shift DATA into SERIALIN register (active HIGH) V

DD3

14 ground for the spindle motor drivers

16 general power supply 17 general ground

25 power supply 1 for the spindle motor drivers

31 ground 3 for the actuator driver

33 VCM voltage control input 34 switchable VCM voltage control input

36 voltage reference input

40 power supply 3 for the actuator driver

1997 Jul 10 4

Philips Semiconductors Product speciﬁcation

Brushless DC motor and VCM drive circuit

TDA5341

with speed control

SYMBOL PIN DESCRIPTION

DDD

ENABLE 42 enable input; enables the serial port, i.e. allows DATA to be shifted in (active LOW) RESETOUT 43 under-voltage detector output ﬂag (active LOW) UVDIN1 44 external capacitor for the VCM− 45 negative output of the VCM ampliﬁer BRAKEDELAY 46 delay control input for brake after park TP2 47 test purpose 2 (should be left open-circuit) ROSC 48 reference oscillator input for motor speed control V

EE4

EED

SENSEIN− 51 inverting input of the VCM sense ampliﬁer SENSEN+ 52 non-inverting input of the VCM sense ampliﬁer SENSEOUT 53 output of the VCM sense ampliﬁer UVDIN2 54 external voltage reference for the under-voltage detector V

EE2

TP3 56 test purpose 3 (should be left open-circuit) RESET 57 reset input; forces all bits of the SERIALIN register to 0 (active HIGH) FMOT 58 tachometer output (one pulse per mechanical revolution) CAPXB 59 external capacitor for the charge pump output MOT1 60 motor driver output 1 CAPXA 61 external capacitor for the charge pump output CAPYA 62 external capacitor for the charge pump output CAPYB 63 external capacitor for the charge pump output V

DD2

41 digital power supply

RESETOUT duration

49 ground 4 for the actuator driver 50 digital ground

55 ground 2 for the spindle motor drivers

64 power supply for the spindle motor drivers

1997 Jul 10 5

Philips Semiconductors Product speciﬁcation

Brushless DC motor and VCM drive circuit with speed control

handbook, full pagewidth

DD2

CAPYB

CAPST

CAPTI

CLAMP1

AMPOUT

AMPIN− AMPIN+

MOT0 MOT2

FREDENA

BRAKE

TESTIN

TP1

EE1

GAINSEL

64 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16

CAPYA

CAPCDS

CAPCDM

CAPXA

MOT1

MOT3

PRESET

FMOT

CAPXB 59

TDA5341

ILIM

CAPCPC

RESET 57

CNTRL

TP3 56

DD1

EE2

UVDIN2

CAPCP

CLAMP2

SENSEIN+

SENSEOUT 53

FB2

FB1

EED

SENSEIN−

EE3

RETRACT

EE4

48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33

FILTER

TDA5341

ROSC TP2 BRAKEDELAY VCM− UVDIN1 RESETOUT ENABLE

DDD

DD3

CLOCK DATA VCM+ V

ref DPULSE V

CMIN2 V

CMIN1

MGE816

Fig.2 Pinning diagram.

1997 Jul 10 6

Philips Semiconductors Product speciﬁcation

Brushless DC motor and VCM drive circuit with speed control

FUNCTIONAL DESCRIPTION

The TDA5341 offers a sensorless three-phase motor full-wave drive function. The device also offers protected outputs capable of handling high currents and can be used with star or delta connected motors.

The TDA5341 can easily be adapted for different motors and applications.

The TDA5341 offers the following features:

• Sensorless commutation by using the motor EMF

• Built-in start-up circuit

• Optimum commutation, independent of motor type or

motor loading

• Built-in flyback diodes

• Three-phase full-wave drive

• High output current (1.3 A)

• Low MOS R

• Outputs protected by current limitation and thermal

protection of each output transistor

• Low current consumption

• Additional uncommitted operational amplifier

• H-bridge actuator driver current controlled with an

external series sense resistor

• Automatic retract procedure

• Adjustable park voltage

• Sleep mode

• Automatic brake (after park) procedure

DSon

(1 Ω)

TDA5341

• Speed control based on FLL technique

• Serial port DATAIN (24 bits)

• Friction reduction prior to spin-up.

TDA5341 modes description

The TDA5341 can be used in two main modes, depending on whether they are controlled or not.

The ‘controlled modes’ (user commands) are executed by the TDA5341 without delay or priority treatment, either by software via the serial port or by hardware. BRAKE is a hardware command whereas RETRACT can be controlled in both ways. If it is preferable to control the heads parking via the serial bus, the equivalent pin can be left open-circuit.

The sleep mode is controlled by software only; it results from the combination of the spindle and actuator being disabled. The spindle is turned off by bit SPINDLE DISABLE, whereas the actuator is disabled towards bit VCM DISABLE of the serial port (see Section “Serial port”). In addition, a special spin-up mode can be activated in the event of high head stiction

The ‘uncontrolled modes’ only result from different failures caused by either a too high internal temperature or an abnormally low power voltage, which will cause the actuator to retract and, after the spindle, to brake. The output signals mainly affected by those failures are RESETOUT, MOT1, 2 and 3, VCM+ and VCM−. This is summarised in Tables 1 and 2.

Table 1 Summary of controlled modes

HARDWARE/

SOFTWARE

Software spindle disable high impedance high impedance HIGH spindle off Software VCM disable not affected high impedance HIGH spindle on; VCM off Hardware brake LOW not affected HIGH spindle coils ground Software/

hardware Hardware friction reduction − not affected HIGH heads in vibration

1997 Jul 10 7

MODE MOT1, 2 AND 3

retract not affected VCM− = 0.65 V;

VCM+ AND

VCM−

VCM+=0V

RESETOUT EFFECT

HIGH heads parked

Philips Semiconductors Product speciﬁcation

Brushless DC motor and VCM drive circuit with speed control

Table 2 Summary of uncontrolled modes

FAILURE MOT1, 2 AND 3 VCM+ AND VCM− RESETOUT EFFECT

Thermal shut-down

Voltage shut-down

Controlled modes

PINDLE DISABLE

The spindle circuitry is switched off when bit 23 (SPINDLE DISABLE) of the serial port is pulled HIGH. In that mode, the reference band gap generator is cut off so that all internal current sources are disabled. Both the spindle and actuator outputs will be set to the high impedance state because the upper converter is also turned off.

It should be noted that the uncommitted operational amplifier is also disabled in that mode.

VCM

DISABLE

The actuator will be disabled when bit 22 (VCM DISABLE) is set to logic 1; the spindle circuitry is not affected in that mode. The retract circuitry also remains active, so that the heads can be parked although the VCM is disabled. In that mode, the current consumption can be reduced by ±4 mA.

high impedance → LOW VCM− = 0.65 V;

VCM+ = 0 V

high impedance → LOW VCM− = 0.65 V;

VCM+ = 0 V

RICTION REDUCTION

F Pulling FREDENA HIGH activates the friction reduction

mode of the TDA5341. In that mode, a clock signal fed via pin TESTIN will cause the MOT outputs to sequentially switch-on and switch-off at the same frequency and, as a result, generate an AC spindle torque high enough to overcome the head stiction.

Before start-up, the head stiction might be higher than normal due to condensation between the head(s) and the disk(s). Normal spin-up is not possible when this friction torque is higher than the start-up torque of the spindle motor. Spin-up is then only possible after friction has been reduced by breaking the head(s) free. Bringing a static friction system into mechanical resonance is an effective method to break static friction head(s) free.

The resonance frequency is:

res



×=

------ -



2π

LOW automatic park and brake



0.5

--- -



TDA5341

LEEP MODE

The sleep mode is obtained by pulling both the SPINDLE and VCM DISABLE bits of the serial port HIGH. The power monitor circuitry only remains active in sleep mode.

ETRACT

R Retract is activated by pulling either bit 21 (PARK) HIGH

or RETRACT (pin 30) LOW. WhenRETRACT is set LOW, a voltage of 0.65 V is applied to pin VCM− for parking.

It should be noted that the park voltage can be made adjustable by changing one of the interconnect masks. Accordingly, some different voltages, varying from

0.2 to 1.2 V, can quickly be obtained on customer demand. This mode does not affect the control of the spindle rotation.

RAKE MODE

The brake mode is activated by pulling BRAKE (pin 11) LOW. When a voltage of less than 0.8 V is applied to pin BRAKE, the 3 motor outputs are short-circuited to ground, which results in a quick reduction of the speed until the motor stops completely.

Where:

C = Stiffness of the head-spring(s) in direction of disk(s) rotation, (N/m)

J = Inertia of the disk(s), (kg/m

The external clock input frequency must be:

clk



------ -



2π



0.5

×=

--- -



A burst of n × 6 clock pulse will bring the system into resonance and break the heads free (n > 2). Once the heads have been broken free, the normal spin-up procedure can be applied.

It should be noted that the clock frequency must be smaller than 40000/CAPCDM (nF).

1997 Jul 10 8

Philips Semiconductors Product speciﬁcation

Brushless DC motor and VCM drive circuit with speed control

Uncontrolled modes

OWER SHUT-DOWN

If the power supply decreases to less than the voltage threshold determined by the ratio between R1 and R2 connected to UVDIN2 (see Fig.8) (for more than 1 µs), the TDA5341 will issue a reset (RESETOUT goes LOW) and the following operation will start:

• Firstly, the MOT outputs are switched to the high impedance state so as to get back the rectified EMF issued from the motor itself. At the same time, the voltage upper converter is cut off in order to preserve the voltage on the charge pump capacitance at CAPCP. The energy supplied in that way is then used to park the heads in a safe position

• Secondly, after a certain period of time, depending on the RC constant of the device connected to BRAKEDELAY, the lower MOS drivers will be turned on in order to stop the motor completely.

TDA5341

The system will only function when the EMF voltage from the motor is present. Consequently, a start oscillator is provided that will generate commutation pulses when no zero-crossings in the motor voltage are available.

A timing function is incorporated into the device for internal timing and for timing of the reverse rotation detection.

The TDA5341 also contains a control amplifier, directly driving output amplifiers.

The TDA5341 also provides access to the user of some of its internal test modes. Firstly, a PRESET mode can be used for prepositioning the three motor output drivers into a fixed state. By pulling pin PRESET to 0.75 V above V MOT3 goes HIGH, MOT2 goes LOW and MOT1 goes to the high impedance state.

In addition, when TESTIN is pulled HIGH (provided that FREDENA is LOW), the 3 motor output drivers are switched off. It should be noted that RESETOUT goes LOW in that particular event.

HERMAL SHUT-DOWN

Should the temperature of the chip exceed +140 ±10 °C, a shut-down operation will also be processed. The actions described for power shut-down will be sequenced in the same manner.

PINDLE SECTION (see Fig.1)

S Full-wave driving of a three-phase motor requires three

push-pull output stages. In each of the six possible states two outputs are active, one sourcing current and one sinking current. The third output presents a high impedance to the motor which enables measurement of the motor EMF in the corresponding motor coil by the EMF comparator at each output. The commutation logic is responsible for control of the output transistors and selection of the correct EMF comparator.

The zero-crossing in the motor EMF (detected by the comparator selected by the commutation logic) is used to calculate the correct moment for the next commutation, i.e. the change to the next output state. The delay is calculated (depending on the motor loading) by the adaptive commutation delay block.

Because of high inductive loading the output stages contain flyback diodes. The output stages are also protected by a current limiting circuit and by thermal protection of the six output transistors.

The zero-crossings can be used to provide speed information such as the tacho signal (FG).

Adjustments

The system has been designed in such a way that the tolerances of the application components are not critical. However, the approximate values of the following components must still be determined:

• The start capacitor; this determines the frequency of the start oscillator

• The two capacitors in the adaptive commutation delay circuit; these are important in determining the optimum moment for commutation, depending on the type and loading of the motor

• The timing capacitor; this provides the system with its timing signals.

The start capacitor (CAPST)

This capacitor determines the frequency of the start oscillator. It is charged and discharged, with a current of

5.5 µA, from 0.05 to 2.2 V and back to 0.05 V. The time

taken to complete one cycle is given by: t

= (0.78 × C); where C is given in µF.

start

The start oscillator is reset by a commutation pulse and so is only active when the system is in the start-up mode. A pulse from the start oscillator will cause the outputs to change to the next state (torque in the motor). If the movement of the motor generates enough EMF the TDA5341 will run the motor.

1997 Jul 10 9

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