Data Sheet PD No. 60179-I
IR21571
(S)
FULLY INTEGRATED BALLAST CONTROL IC
Features
•
Programmable preheat time & frequency
•
Programmable ignition ramp
•
Protection from failure-to-strike
•
Lamp filament sensing & protection
•
Protection from operation below resonance -
•
•
•
Thermal overload protection
•
Programmable deadtime
•
Integrated 600V level-shifting gate driver
•
Internal 15.6V zener clamp diode on VCC
•
Micropower startup (150uA)
•
Latch immunity protection on all leads
•
ESD protection on all leads
0.2V CS threshold sync’d to falling edge on LO
Protection from low-line condition
Automatic restart for lamp exchange
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
Typical Connection
+ Rectified AC Line
+ V
BUS
R2
R1
VDC
HO
R
Supply
1
16
VS
C1
C
PH
C
RAMP
R
T
C
START
R
START
C
T
R
OC
R
DT
R
PH
R
RUN
CPH
R
GHS
C
BS
D
BOOT
C
VCC
D1
C
BLOCK
L
RES
2
RPH
15
VB
IR21571
3
RT
14
VCC
C
SNUBBER
4
RUN
13
COM
5
CT
12
D2
LO
C
RES
6
DT
11
CS
R3
R
GLS
R5
R4
7
OC
10
SD
8
9
C2
R
CS
V
BUS
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