On Semi CAT4106 6W多路LED驱动方案
On Semi(安森美)公司的 CAT4106是多路LED驱动器和大功率DC/DC转换器,适用于六瓦的背景光供电. CAT4106集成了DC/DC升压转换器,四路LED驱动有非常好的电流匹配,效力高达92%,LED通路的压降低,在175mA时为500mV,高频PWM接口高达2kHz,主要用于LCD背景光照明和汽车与通用照明.本文介绍了CAT4106的主要特性,方框图和驱动一串与两串LED典型应用电路.The CAT4106 is an integrated multi-channel LED driver and high power DC/DC converter suitable for powering backlighting applications up to a total of 6 watts. Up to four matched LED strings can be accurately programmed with uniform drive current set by a single external resistor. Each output channel is suitable for LED string voltages of up to 36 V. The driver automatically adjusts the output voltage to drive the highest forward voltage string with the minimum headroom voltage maximizing the efficiency.
High resolution dimming control is achieved by the EN/PWM logic pin which supports multiple frequencies. This ensures precise PWM dimming control while the device remains fully biased. In addition, when held at logic low, the device to enter a full shutdown “zero” current mode.
External programming resistors set the minimum and maximum voltage limits for the acceptable “window of operation” for LED strings. Any channel which fails to regulate within the window (Open or Short LED) is detected and flagged on the FAULT logic output(active low, open-drain).
The device is available in a 16-lead TQFN 4 mm x 4 mm and TSSOP with exposed pad packages.
CAT4106主要特性:
Four LED Channels with tight current matching
Integrated DC/DC Boost converter
Up to 6 W LED Total Output Power
Up to 92% Efficiency
Low Dropout LED Channels (500 mV at 175 mA)
High Frequency PWM interface (up to 2 kHz)
Adjustable Short/Open LED Detection
Programmable LED Channel current
Adjustable LED Channel voltage
Thermal shutdown protection
RoHS-compliant 16-lead TQFN 4 x 4 mm and TSSOP packages
CAT4106应用:
LCD Backlight Lighting
Automotive and General Purpose Lighting
图1.CAT4106方框图
图2.CAT4106典型应用电路图
图3.驱动一串LED的应用电路图
图4.驱动两串LED的应用电路图
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