LAB

SEME

IP1525A SERIES

IP1527A SERIES

Prelim. 3/95

Q

Q

PWM

INV.

INPUT

N.I.

INPUT

1

2

ERROR

AMP

T

T

OSCILLATOR

R

C

OSC. OUTPUT

6

5

TO INTERNAL

CIRCUITRY

V

REF

16

15

12

REFERENCE

REGULATOR

GND

+V

IN

3

SYNC

4

DISCHARGE

+V

IN

COMPENSATION

SOFT START

8

V

REF

50

µA

SHUTDOWN

10

5k

Ω

U.V.

LOCKOUT

FLIP

FLOP

S

R

LATCH

OUTPUT A

11

14

13

OUTPUT B

5k

Ω

9

7

IP1525A OUTPUT STAGE

OUTPUT A

11

14

13

OUTPUT B

IP1527A OUTPUT STAGE

+8 to +35V

+4.5 to +35V

0 to 100mA

0 to 400mA

0 to 20mA

100Hz to 400kHz

2k

Ω to 200kΩ

470pF to 0.1

µF

0 to 500

Ω

–55 to +125°C

0 to +70°C

RECOMMENDED OPERATING CONDITIONS

BLOCK DIAGRAM

Input Voltage

Collector Voltage

Sink/Source Load Current (Steady State)

Sink/Source Load Current (Peak)

Reference Load Current

Oscillator Frequency Range

Oscillator Timing Resistor

Oscillator Timing Capacitor

Deadtime Resistor Range

Operating Ambient Temperature Range

IP1525A / IP1527A

IP3525A / IP3527A

DESCRIPTION

The IP1525A and IP1527A families of PWM switching regulator control circuits offer improved performance and lower

parts count when used in designing switching power supplies. Included are 5.1 volt reference, error amplifier, adjustable

dead-time oscillator with synchronisation capability, latched PWM comparator, totem-pole output drivers, shutdown, soft

start, and undervoltage lockout.

The IP1525A and IP1527A differ only in output phasing. The IP1525A output is low when “off”, while the IP1527A

output is high when “off”.