安森美(On Semi)公司的CAT4106是带诊断功能的6W四路LED驱动器,它集成了多路LED驱动器和大功率DC/DC转换器,适合用于6W功率的背景光供电. CAT4106的效率高达92%,高达2kHz的高频PWM接口,可调的LED短路/开路检测以及LED通路电压(高达36V)和热关断保护,可用在LCD背景光照明和汽车以及通用照明.本文介绍了CAT4106的主要特性, 简化的功能方框图, 典型应用电路以及一路和两路LED串应用电路.
CAT4106: 6W Quad Channel DC/DC LED Driver with Diagnostics
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典型应用电路
图2.CAT4106简化的功能方框图
图3.CAT4106的一路LED串应用电路
图4.CAT4106的两路LED串应用电路
