Supertex inc.
LED Driver with Average-Mode,
Constant Current Control
Features
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Fast average current control
Programmable constant off-time switching
PWM / linear dimming input
Output short circuit protection with skip mode
Ambient operating temperature -40
O
C to +125
O
C
Pin-compatible with the HV9910B and HV9961
HV9861A
General Description
The HV9861A is a patented, average-mode, constant current control
LED driver IC operating in a constant off-time mode. Unlike the
HV9910B, this control IC does not produce a peak-to-average error,
and therefore greatly improves the accuracy, line and load regulation
of the LED current without any need for loop compensation or high-
side current sensing. The output LED current accuracy is ±3%.
The IC is equipped with a current limit comparator for hiccup-mode
output short circuit protection. Internal over-temperature protection
is provided. The internally regulated voltage (V
DD
) for the HV9861A
is 7.5V.
The IC can be powered from a 12 - 450V supply. A PWM dimming
input is provided that accepts an external control TTL-compatible
signal. The output current can be programmed by an internal 270mV
reference, or controlled externally through a 0 - 1.5V dimming input.
The IC is pin-to-pin compatible with the Supertex HV9910B and
HV9961, and can be used as a drop-in replacement for many
applications to improve the LED current accuracy and regulation.
Applications
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DC/DC or AC/DC LED driver applications
LED backlight driver for LCD displays
General purpose constant current source
LED signage and displays
Architectural and decorative LED lighting
LED street lighting
Typical Application Circuit
12 to
450VDC
LED
Load
1
VIN
5 PWMD
GATE 4
HV9861A
6 VDD
7 LD
GND
3
CS 2
RT 8
RT
RCS
Sets
LED
Current
Supertex inc.
1235 Bordeaux Drive, Sunnyvale, CA 94089
Tel: 408-222-8888
www.supertex.com
SUPERTEX [ Supertex, Inc ]
