HV9911
Switch-Mode LED Driver IC with High Current Accuracy
Features
►
Switch mode controller for single switch drivers
o Buck
o Boost
o Buck-boost
o SEPIC
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Works with high side current sensing
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Closed loop control of output current
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High PWM dimming ratio
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Internal 250V linear regulator (can be extended
using external zener diodes)
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Internal 2% Voltage Reference (0°C < T
A
< 85°C)
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Constant frequency or constant off-time operation
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Programmable slope compensation
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Enable & PWM dimming
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+0.2A/-0.4A gate drive
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Output short circuit protection
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Output over voltage protection
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Synchronization capability
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Programmable MOSFET current limit
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Soft start
General Description
The HV9911 is a current mode control LED driver IC
designed to control single switch PWM converters (buck,
boost, buck-boost, or SEPIC), in a constant frequency or
constant off-time mode. The controller uses a peak current
control scheme, (with programmable slope compensation),
and includes an internal transconductance amplifier to
control the output current in closed loop, enabling high
output current accuracy. In the constant frequency mode,
multiple HV9911s can be synchronized to each other, or
to an external clock, using the SYNC pin. Programmable
MOSFET current limit enables current limiting during input
under voltage and output overload conditions. The IC also
includes a 0.2A source and 0.4A sink gate driver for high
power applications. An internal 9 to 250V linear regulator
powers the IC, eliminating the need for a separate power
supply for the IC. HV9911 provides a TTL compatible, PWM
dimming input that can accept an external control signal
with a duty ratio of 0-100% and a frequency of up to a few
kilohertz. The IC also provides a FAULT output which, can
be used to disconnect the LEDs in case of a fault condition,
using an external disconnect FET.
The HV9911 based LED driver is ideal for RGB backlight
applications with DC inputs. The HV9911 based LED lamp
drivers can achieve efficiency in excess of 90% for buck
and boost applications.
Applications
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►
►
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RGB backlight applications
Automotive LED driver application
Battery Powered LED lamps
Other DC/DC LED drivers
Typical Application Circuit - Boost
C
IN
1
VIN
GATE
3
L1
D1
Q1
R
OVP1
C
O
C
DD
2
VDD
CS
5
R
SC
R
CS
R
OVP2
4
GND
OVP
12
R
SLOPE
6
SC
HV9911
FAULT
11
Q2
R
T
7
RT
FDBK
16
C
REF
C
c
10 REF
COMP 14
R
s
R
L2
9
CLIM
PWMD 13
R
L1
15 IREF
SYNC
8
R
R1
R
R2
SUPERTEX [ Supertex, Inc ]
