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 pro-

grammable features such as preheat time & frequency, ignition ramp characteris-

tics, and running mode operating frequency provide a high degree of flexibility for

the ballast design engineer. Comprehensive protection features such as protec-

tion 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 accomplished 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

www.irf.com

1

IR21571(S) & (PbF)

Not recommended for new design:

please use IRS21571D

Data Sheet PD No. 60179 revM