TIL5942, TIL5942A

CURRENT-MODE-PWM CONTROLLER

WITH OPTOISOLATED VOLTAGE REFERENCE AND ERROR AMPLIFIER

SOES040 – OCTOBER 1997

2

POST OFFICE BOX 655303

functional block diagram

Voltage

Reference

Voltage

Regulator

Oscillator

DQ

CLK

R

Driver

LED

Primary

Secondary

TL1431X

11

13

12

14

4

3

1

2

1V

10

9

16

15

REG

OUT

IS

VC

VCC

PWM_GND

REF

RT/CT

BIAS

COMP

FB

INPUT_GND

I(VC)

IIB(IS)

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

FB

1

I

Feedback. FB is an error-amplifier inverting input.

INPUT_GND

2

I

Ground connection for the voltage reference/error amplifier section.

COMP

3

O

Error amplifier output/LED cathode connection. RC networks may be connected between COMP, FB, and

GND to stabilize the control loop of the dc/dc converter.

BIAS

4

I

Optocoupler LED anode. BIAS connects to the output voltage of the dc/dc converter or to some other suitable

supply voltage through a resistor.

NC

7,8

No connection.

OUT

9

O

Drive output. OUT is a pulse-width-modulated output.

REG

10

O

Regulator output. A 0.1-

µF, typical, ceramic capacitor should be connected between REG and PWM_GND.

VCC

11

I

Supply voltage for PWM controller

REF

12

O

PWM 5-V reference output

PWM_GND

13

I

PWM ground connection

RT/CT

14

Connection for external RC network to set PWM oscillator frequency

VC

15

Connection for integrating capacitor (0.1

µF typ) to PWM_GND (terminal 13)

IS

16

I

PWM current sense input