Features

0.2V CS threshold sync’d to falling edge on LO

FULLY INTEGRATED BALLAST CONTROL IC

Typical Connection

Description

The IR21571 is a fully integrated, fully protected 600V ballast control IC designed to

drive virtually all types of rapid start fluorescent lamp ballasts. Externally program-

mable features such as preheat time & frequency, ignition ramp characteristics, and

running mode operating frequency provide a high degree of flexibility for the ballast

design engineer. Comprehensive protection features such as protection from failure of

a lamp to strike, filament failures, low dc bus conditions, thermal overload, or lamp

failure during normal operation, as well as an automatic restart function, have been

included in the design. The heart of this control IC is a variable frequency oscillator

with externally programmable deadtime. Precise control of a 50% duty cycle is accom-

plished using a T-flip-flop. The IR21571 is available in both 16 pin DIP and 16 pin narrow

body SOIC packages.

Packages

16 Lead SOIC

(narrow body)

16 Lead PDIP

+ V

BUS

+ Rectified AC Line

V

R

PH

R

RUN

C

START

R

START

R

T

C

T

C

RAMP

C

PH

R

DT

C

BS

D

BOOT

R

Supply

C

VCC

R

CS

L

RES

C

RES

R

GHS

R

GLS

C

BLOCK

C

SNUBBER

R1

R2

C1

R

OC

R4

R3

R5

C2

D1

D2

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

VDC

CPH

RPH

RT

RUN

CT

DT

OC

LO

COM

VCC

VB

VS

HO

SD

CS

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Data Sheet PD No. 60179-I