Preliminary Technical Data
Four-String, White LED Driver
for LCD Backlight Applications
White LED driver based on an inductive boost controller
Wide input voltage range: 4.5 V to 40 V
Adaptive output voltage to minimize power dissipation
Adjustable operating frequency: 200 kHz to 1.2 MHz
Programmable soft start time for boost converter
Programmable external MOSFET switching rising/falling time
Drives up to 4 LED current sinks with internal MOSFETs
Brightness control with PWM input
Adjustable LED current: 40 mA up to 200 mA
Headroom control to maximize efficiency
LED dimming frequency: up to 25 kHz
1000:1 PWM dimming at 300 Hz
Open drain fault indicator
LED open and LED short fault protection
24-lead, 4 mm × 4 mm LFCSP
LCD monitor and TV LED backlights
The ADD5211 is a 4 channel, white LED driver for backlight
applications based on high efficiency, current mode, step-up
converter technology. The boost controller drives an external
MOSFET switch for step-up regulation from an input voltage of
4.5 V to 40 V and a pin adjustable operating frequency between
200 kHz and 1.2 MHz. An adjustable UVLO function is
implemented to reduce input current during power-off.
The ADD5211 contains four regulated current sinks for uniform
brightness intensity. Each current sinks can be driven from 40
mA up to 200 mA and the LED driving current is pin adjustable
by an external resistor. The ADD5211 with an input PWM
interface drives up to four parallel strings of multiple series
connected LEDs with ±1.5% current matching between strings.
Additional features include fault indicator output LED short
protection, LED open protection, boost output short protection,
overvoltage protection, cycle-by-cycle current limit, and
thermal shutdown for both the IC and LED array. The
programmable soft start is implemented to reduce inrush
current during startup.
VIN GATE_P GATE_N
AGND FREQ COMP
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