LM36274 Texas instruments

LM36274

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LM36274

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Описание

The LM36274 is an integrated four-channel WLED driver and LCD bias supply. The ultra-compact size, high efficiency, high level of integration, and programmability allow the LM36274 to address a variety of applications without the need for hardware changes while minimizing the overall solution area.The backlight boost provides the power to bias four parallel LED strings with up to 29-V total output voltage. The 11-bit LED current is programmable via the I2C bus and/or controlled via a logic level PWM input from 60 µA to 30 mA. Each LED string can be independently enabled or disabled to provide zone dimming capabilities. The backlight boost can be operated efficiently with an inductance range from 4.7 µH to 15 µH, allowing for efficiency and solution size optimization. The LCD bias boost provides the power to both a positive LDO and an inverting charge pump. Both positive and negative bias supplies have programmable output voltages of ±4 V to ±6.5 V with 50-mV steps and up to ±80 mA of current capability. An auto-sequencing feature provides a programmed delay from positive to negative bias activation, with additional programmable voltage slew rate control. Two wake-up modes allow both bias outputs to be controlled with a single external signal and stay active while consuming very low quiescent current.

Drives up to Four Parallel White LED Strings
(29-V Maximum V_OUT)
11-Bit Exponential and Linear Dimming Control
PWM and I²C Brightness Control
Backlight Operation With 4.7-µH to 15-µH Inductor
Backlight and LCD Bias Efficiency up to 92%
Programmable LCD Bias Voltages (±4 V to ±6.5 V With 50-mV resolution) With Up to 80-mA per Output
0.2% Matched LED Current From 60 µA to 30 mA
1% Accurate LED Current From 60 µA to 30 mA
2.7-V to 5-V Input Voltage Range

Number of channels	4
Vin (min) (V)	2.7
Vin (max) (V)	5
Vout (min) (V)	27
Vout (max) (V)	30
Type	Inductive
Switching frequency (max) (kHz)	1050
Duty cycle (max) (%)	92
LED current per channel (mA)	30
Peak efficiency (%)	92
Topology	Boost, Current Sink
Features	Adjustable Switch Frequency, CABC, I2C control, OVP, Thermal shutdown
Operating temperature range (°C)	-40 to 85
Rating	Catalog