Supertex inc.
AT9932
Automotive Boost-Buck
LED Lamp Driver IC
Features
General Description
The AT9932 is an advanced fixed frequency PWM
controller IC designed to control an LED lamp driver using
a boost-buck topology that can step the input voltage up
or down automatically. The IC provides fast output current
transient response and very low susceptibility to input
voltage transients, which allows the lamp driver to pass the
rigorous electrical transient requirements of SAE J1455 or
ISO 7637-2, making the AT9932 an ultimate solution for
automobile lighting. Capacitive isolation protects the LED
Lamp from failure of the switching MOSFET.
► Constant output current
► Steps output voltage up or down
► Very low susceptibility to Input voltage transients
► Frequency jitter
► Externally programmable fixed switching frequency
► Temperature foldback with external NTC resistor
► Internal 40V voltage regulator
► +/-1A MOSFET gate driver
► Short LED protection
► Open LED protection
The AT9932 features a unique feed-forward current control
scheme, differential output current sensing, soft start,
protection from short or open LED load. Switching frequency
can be programmed with a single external resistor.
► Input undervoltage protection
► Enable & PWM dimming
► Trimmed reference (±3% accurate)
► AEC-Q100 compliant
The AT9932 includes a temperature fold-back of the output
current using an external NTC resistor. This feature allows
maximizing the light output of the LED load over the entire
operating temperature range.
Applications
► Automobile lighting
► Battery powered LED lamps
► Other low voltage AC/DC or DC/DC LED drivers
Typical Application Circuit
C1
L2
L1
CO
Rd
CIN
Cd
M1
VIN
AVDD
GATE
FFP
RIN
D1
RP
ZD1
PVDD
LED(s)
RN
CVDD
FFN
REF
PWMD
UVLO
ROV
RFB
RT
RREF
RINC
FLT
FB
RT
RFLT
SS
RS
CSS
RDRP
PGND
GND
CREF
DRP
CC
RNTC
COMP
NTC
T1
R3
T2
R2
R1
CJTR
DIV
JTR
AT9932
Supertex inc. ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: 408-222-8888 ● www.supertex.com