UNITRODE UC1625, UC2625, UC3625 Technical data

5962-9168901MXA

application

INFO

available

UC1625

UC2625

UC3625

Brushless DC Motor Controller

FEATURES

•Drives Power MOSFETs or Power Darlingtons Directly

•50V Open Collector High-Side Drivers

•Latched Soft Start

•High-speed Current-Sense Amplifier with Ideal Diode

•Pulse-by-Pulse and Average Current Sensing

•Over-Voltage and Under-Voltage Protection

•Direction Latch for Safe Direction Reversal

•Tachometer

•Trimmed Reference Sources 30mA

•Programmable Cross-Conduction Protection

•Two-Quadrant and Four-Quadrant Operation

DESCRIPTION

The UC3625 family of motor controller ICs integrate most of the functions required for high-performance brushless DC motor control into one package. When coupled with external power MOSFETs or Darlingtons, these ICs perform fixed-frequency PWM motor control in either voltage or current mode while implementing closed loop speed control and braking with smart noise rejection, safe direction reversal, and cross–conduction protection.

Although specified for operation from power supplies between 10V and 18V, the UC1625 can control higher voltage power devices with external level-shifting components. The UC1625 contains fast, high-current push-pull drivers for low-side power devices and 50V open-collector outputs for high-side power devices or level shifting circuitry.

The UC1625 is characterized for operation over the military temperature range of –55°C to +125°C, while the UC2625 is characterized from –40°C to +105°C and the UC3625 is characterized from 0°C to 70°C. (NOTE: ESD Protection to 2kV)

TYPICAL APPLICATION

VREF

+5V TO HALL

+15V

VMOTOR

SENSORS

3kΩ

100nF

100µF

2N3904

20µF

10Ω

10kΩ

3kΩ

10kΩ

QUAD

ROSC

2N3906

33kΩ

3kΩ

IRF9350

DIR

TO OTHER

MOTOR

CHANNELS

100nF

UC3625

4kΩ

REQUIRED

TO OTHER

FOR BRAKE

CHANNELS

AND FAST

REVERSE

2200pF

10Ω

IRF532

COSC

BRAKE

10kΩ

3nF

68kΩ

100nF

5nF

100nF

240Ω

REQUIRED

FROM

FOR

HALL

0.02Ω

AVERAGE

2nF

SENSORS

5nF

240Ω

CURRENT

SENSING

2nF

0.02Ω

2nF

UDG-99045

SLUS353A - NOVEMBER 1999

ABSOLUTE MAXIMUM RATINGS

VCC Supply Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +20V

Pwr VCC Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . +20V PWM In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 to 6V

E/A IN(+), E/A IN(–) . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 to 12V

ISENSE1, ISENSE2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . –1.3 to 6V OV–Coast, Dir, Speed-In, SSTART, Quad Sel . . . . . . –0.3 to 8V

H1, H2, H3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 to 12V PU Output Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 to 50V PU Output Current . . . . . . . . . . . . . . . . . . +200 mA continuous PD Output Current . . . . . . . . . . . . . . . . . . ±200 mA continuous E/A Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±10 mA

ISENSE Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . –10 mA Tach Out Output Current . . . . . . . . . . . . . . . . . . . . . . . . ±10 mA

VREF Output Current . . . . . . . . . . . . . . . . . . –50 mA continuous Operating Temperature Range UC1625. . . . . . –55°C to 125°C

Operating Temperature Range UC2625. . . . . . –40°C to 105°C Operating Temperature Range UC3625. . . . . . . . . 0°C to 70°C

Note 1: Currents are positive into and negative out of the specified terminal.

Note 2: Consult Unitrode Integrated Circuits databook for information regarding thermal specifications and limitations of packages.

UC1625

UC2625

UC3625

CONNECTION DIAGRAM

DIL-28 (TOP VIEW)

J or N PACKAGE

Note 3: This pinout applies to the SOIC (DW), PLCC (Q), and LCC (L) packages (ie. pin 22 has the same function on all packages.)

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for: TA = 25°C; Pwr VCC = VCC = 12V; ROSC = 20k to VREF; COSC = 2nF; RTACH = 33k; CTACH = 10nF; and all outputs unloaded. TA = TJ.

PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNITS
Overall
Supply current	Over Operating Range		14.5	30.0	mA
VCC Turn-On Threshold	Over Operating Range	8.65	8.95	9.45	V
VCC Turn-Off Threshold	Over Operating Range	7.75	8.05	8.55	V
Overvoltage/Coast
OV-Coast Inhibit Threshold	Over Operating Range	1.65	1.75	1.85	V
OV-Coast Restart Threshold		1.55	1.65	1.75	V
OV-Coast Hysteresis		0.05	0.10	0.15	V
OV-Coast Input Current		–10	–1	0	A
Logic Inputs
H1, H2, H3 Low Threshold	Over Operating Range	0.8	1.0	1.2	V
H1, H2, H3 High Threshold	Over Operating Range	1.6	1.9	2.0	V
H1, H2, H3 Input Current	Over Operating Range, to 0V	-400	-250	–120	A
Quad Sel, Dir Thresholds	Over Operating Range	0.8	1.4	2.0	V
Quad Sel Hysteresis			70		mV
Dir Hysteresis			0.6		V
Quad Sel Input Current		–30	50	150	A
Dir Input Current		–30	–1	30	A
PWM Amp/Comparator
E/A In(+), E/A In(–) Input Current	To 2.5V	–5.0	–0.1	5.0	A
PWM In Input Current	To 2.5V	0	3	30	A
Error Amp Input Offset	0V < VCOMMON-MODE < 3V	–10		10	mV
Error Amp Voltage Gain		70	90		dB

UC1625

UC2625

UC3625

PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNITS
PWM Amp/Comparator (cont.)
E/A Out Range		0.25		3.50	V
SSTART Pull-up Current	To 0V	–16	–10	–5	A
SSTART Discharge Current	To 2.5V	0.1	0.4	3.0	mA
SSTART Restart Threshold		0.1	0.2	0.3	V
Current Amp
Gain	ISENSE1 = .3V, ISENSE2 = .5V to .7V	1.75	1.95	2.15	V/V

Level Shift	ISENSE1 = .3V, ISENSE2 = .3V	2.4	2.5	2.65	V
Peak Current Threshold	ISENSE1 = 0V, Force ISENSE2	0.14	0.20	0.26	V
Over Current Threshold	ISENSE1 = 0V, Force ISENSE2	0.26	0.30	0.36	V
ISENSE1, ISENSE2 Input Current	To 0V	–850	–320	0	A
ISENSE1, ISENSE2 Offset Current	To 0V		±2	±12	A
Range ISENSE1, ISENSE2		–1		2	V
Tachometer/Brake
Tach-Out High Level	Over Operating Range, 10k to 2.5V	4.7	5	5.3	V
Tach-Out Low Level	Over Operating Range, 10k to 2.5V			0.2	V
On Time		170	220	280	s
On Time Change With Temp	Over Operating Range		0.1		%
RC-Brake Input Current	To 0V	–4.0	–1.9		mA
Threshold to Brake, RC-Brake	Over Operating Range	0.8	1.0	1.2	V
Brake Hysteresis, RC-Brake			0.09		V
Speed-In Threshold	Over Operating Range	220	257	290	mV
Speed-In Input Current		–30	–5	30	A
Low-Side Drivers
Voh, –1mA, Down From VCC	Over Operating Range		1.60	2.1
V Voh, –50mA, Down From VCC	Over Operating Range		1.75	2.2	V
Vol, 1mA	Over Operating Range		0.05	0.4	V
Vol, 50mA	Over Operating Range		0.36	0.8	V
Rise/Fall Time	10% to 90% Slew Time, into 1nF		50		ns
High-Side Drivers
Vol, 1mA	Over Operating Range		0.1	0.4	V
Vol, 50mA	Over Operating Range		1.0	1.8	V
Leakage Current	Output Voltage = 50V			25	A
Fall Time	10% to 90% Slew Time, 50mA Load		50		ns
Oscillator
Frequency		40	50	60	kHz
Frequency	Over Operating Range	35		65	kHz
Reference
Output Voltage		4.9	5.0	5.1	V
Output Voltage	Over Operating Range	4.7	5.0	5.3	V
Load Regulation	0mA to –20mA Load	–40	–5		mV
Line Regulation	10V to 18V VCC	–10	–1	10	mV
Short Circuit Current	Over Operating Range	50	100	150	mA

UC1625

UC2625

UC3625

PARAMETER	TEST CONDITIONS	MIN	TYP	MAX	UNITS
Miscellaneous
Output Turn-On Delay			1		s
Output Turn-Off Delay			1		s

BLOCK DIAGRAM

Quad Sel

VREF

RC-Osc

OSC

REFERENCE

PWM CLOCK

PWM In

E/A Out

E/A In(+)

2.9V

E/A In (–)

10µA

SSTART

ISENSE

ABS VALUE

0.2V

250Ω

ISENSE1

2.5V

ISENSE2

3.1V

VCC

PWM

OV-Coast

CLOCK

1.75V

PUA

Dir

PUB

DIRECTION

Speed-In

LATCH

0.25V

PUC

+5V

PWM CLOCK

DIR

COAST

CHOP

QUAD

Pwr Vcc

CROSS

PDA

CONDUCTION

+5V

PROTECTION

LATCHES

DECODER

+5V

PDB

BRAKE

PDC

EDGE

DETECT

GND

+5V

RC-Brake

ONE

Tach-Out

SHOT

UDG-99044

PIN DESCRIPTIONS

Dir, Speed-In: The position decoder logic translates the Hall signals and the Dir signal to the correct driver signals (PUs and PDs). To prevent output stage damage, the signal on Dir is first loaded into a direction latch, then shifted through a two-bit register.

As long as Speed-In is less than 250mV, the direction latch is transparent. When Speed-In is higher than 250mV, the direction latch inhibits all changes in direction. Speed-In can be connected to Tach-Out through a filter, so that the direction latch is only transparent when the motor is spinning slowly, and has too little stored energy to damage power devices.

Additional circuitry detects when the input and output of the direction latch are different, or when the input and output of the shift register are different, and inhibits all output drives during that time. This can be used to allow the motor to coast to a safe speed before reversing.

The shift register guarantees that direction can't be changed instantaneously. The register is clocked by the PWM oscillator, so the delay between direction changes is always going to be between one and two oscillator periods. At 40kHz, this corresponds to a delay of between 25µs and 50µs. Regardless of output stage, 25µs dead time should be adequate to guarantee no overlap cross-conduction. Toggling DIR will cause an output pulse on Tach-Out regardless of motor speed.

E/A In(+), E/A In(–), E/A Out, PWM In: E/A In(+) and E/A In(–) are not internally committed to allow for a wide

variety of uses. They can be connected to the ISENSE, to Tach-Out through a filter, to an external command volt-

age, to a D/A converter for computer control, or to another op amp for more elegant feedback loops. The error amplifier is compensated for unity gain stability, so E/A Out can be tied to E/A In(–) for feedback and major loop compensation.

E/A Out and PWM In drive the PWM comparator. For voltage-mode PWM systems, PWM In can be connected to RC-Osc. The PWM comparator clears the PWM latch, commanding the outputs to chop.

The error amplifier can be biased off by connecting E/A In(–) to a higher voltage than E/A In(+). When biased off, E/A Out will appear to the application as a resistor to ground. E/A Out can then be driven by an external amplifier.

GND: All thresholds and outputs are referred to the GND pin except for the PD and PU outputs.

UC1625

UC2625

UC3625

H1, H2, H3: The three shaft-position sensor inputs consist of hysteresis comparators with input pull-up resistors. Logic thresholds meet TTL specifications and can be driven by 5V CMOS, 12V CMOS, NMOS, or open-collectors.

Connect these inputs to motor shaft position sensors that are positioned 120 electrical degrees apart. If noisy signals are expected, zener clamp and filter these inputs with 6V zeners and an RC filter. Suggested filtering components are 1kΩ and 2nF. Edge skew in the filter is not a problem, because sensors normally generate modified Gray code with only one output changing at a time, but rise and fall times must be shorter than 20µs for correct tachometer operation.

Motors with 60 electrical degree position sensor coding can be used if one or two of the position sensor signals is inverted.

ISENSE1, ISENSE2, ISENSE: The current sense amplifier has a fixed gain of approximately two. It also has a

built-in level shift of approximately 2.5V. The signal appearing on ISENSE is:

ISENSE = 2.5V + (2 • ABS(ISENSE1 – ISENSE 2 ))

ISENSE1 and ISENSE2 are interchangeable and can be used as differential inputs. The differential signal applied

can be as high as ±0.5V before saturation.

If spikes are expected on ISENSE1 or ISENSE2, they are best filtered by a capacitor from ISENSE to ground. Filtering this way allows fast signal inversions to be cor-

rectly processed by the absolute value circuit. The peak-current comparator allows the PWM to enter a cur- rent-limit mode with current in the windings never exceeding approximately 0.2V/RSENSE. The over current comparator provides a fail-safe shutdown in the unlikely

case of current exceeding 0.3V/RSENSE. Then, soft start is commanded, and all outputs are turned off until the

high current condition is removed. It is often essential to

use some filter driving ISENSE1 and ISENSE2 to reject extreme spikes and to control slew rate. Reasonable start-

ing values for filter components might be 250Ω series

resistors and a 5nF capacitor between ISENSE1 and ISENSE2. Input resistors should be kept small and matched to maintain gain accuracy.

OV-Coast: This input can be used as an over-voltage shutdown in put, as a coast input, or both. This input can be driven by TTL, 5V CMOS, or 12V CMOS.

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