Linear LT3956 80V恒流恒压HBLED驱动方案
Linear 公司的LT3956 是80V输入80V输出恒流恒压DC/DC转换器,非常适合用来驱动大电流高亮度LED(HBLED).3000:1真彩色PWM调光,输入电压从4.5V到80V,输出电压高达80V,内部集成了3.3V/80V开关,可调频率从100kHz到1MHz,能以升压,降压,升降压,SEPIC或反激模式驱动LED,主要用于大功率LED,电池充电器和精密电流限压稳压器.本文介绍了LT3956主要特性,方框图,以及多种应用电路,包括效率95%25W WLED汽车头灯驱动电路图, 升-降压模式LED驱动电路图, 超大电容充电电路图,以及降压模式90W LED驱动电路图等.
80VIN, 80VOUT Constant-Current,Constant-Voltage Converter
The LT®3956 is a DC/DC converter designed to operate as a constant-current source and constant-voltage regulator. It is ideally suited for driving high current LEDs. It features an internal low side N-channel power MOSFET rated for 84V at 3.3A and driven from an internal regulated 7.15V supply. The fixed frequency, current-mode architecture results in stable operation over a wide range of supply and output voltages. A ground referenced voltage FB pin serves as the input for several LED protection features, and also makes it possible for the converter to operate as a constant-voltage source. A frequency adjust pin allows the user to program the frequency from 100kHz to 1MHz to optimize efficiency, performance or external component size.
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