LAB

SEME

IP1524B SERIES

Prelim. 3/95

E

C

C.L.

+C.L.

SENSE

–C.L.

SENSE

INV.

INPUT

N.I.

INPUT

T

T

6

7

OSCILLATOR

R

C

15

8

REFERENCE

REGULATOR

GND

UNDER

VOLTAGE

LOCKOUT

TO INTERNAL

CIRCUITRY

OSC.

D

S Q

Q

S

Q

R

Q

T

Q

1

2

5

4

COMPENSATION

SHUTDOWN

9

10

PWM

LATCH

MEMORY

F/F

TOGGLE

F/F

PWM

ERROR

V

REF

16

3

C

E

B

B

A

A

11

12

13

14

+7 to +40V

0 to +60V

0 to 200mA

0 to 20mA

25

µA to 1.8mA

50Hz to 500kHz

2k

Ω to 150kΩ

1nF to 0.1

µF

–55 to +125°C

–25 to +85°C

0 to +70°C

RECOMMENDED OPERATING CONDITIONS

DESCRIPTION

The IP1524B is a pulse width modulator for switching power supplies which features improved performance over

industry standards like the SG1524. A direct pin-for-pin replacement for the earlier device, it combines advanced

processing techniques and circuit design to provide improved reference accuracy/ and extended common mode range at

the error amplifier and current limit inputs. A DC-coupled flip-flop eliminates triggering and glitch problems, and a PWM

data latch prevents edge oscillations. The circuit incorporates true digital shutdown for high speed response, while an

undervoltage lockout circuit prevents spurious outputs when the supply voltage is too low for stable operation. Full

double-pulse suppression logic insures alternating output pulses when the shutdown pin is used for pulse-by-pulse

current limiting.

BLOCK DIAGRAM

Input Voltage

Collector Voltage

Error Amp Common Mode Range

Current Limit Sense Common Mode Range

Output Current

(each transistor)

Reference Load Current

Oscillator Charging Current

Oscillator Frequency Range

Oscillator Timing Resistor

Oscillator Timing Capacitor

Operating Ambient Temperature Range

IP1524B

IP2524B

IP3524B