Linear LT3496三输出LED驱动方案

Linear 公司的LT3496是三输出DC/DC转换器，能作为恒流工作，非常适合用来驱动LED。可调开关频率在330kHz到1MHz，调光比达3000:1，可工作在降压，升压和降-升压模式，内置了750mA/45V开关的三路独立驱动器，有开路LED保护，主要用在RGB照明，汽车和军用飞机照明，广告牌和大型显示器以及恒流源。本文介绍了LT3496主要特性，方框图，多种应用电路以及LT3496EUFD 评估板主要特性和电路图。

The LTR3496 is a triple output DC/DC converter designed to operate as a constant-current source and is ideal for driving LEDs. The LT3496 works in buck, boost or buckboost mode. The LT3496 uses a fixed frequency, current mode architecture resulting in stable operation over a wide range of supply and output voltages. A frequency adjust pin allows the user to program switching frequency between 330kHz and 2.1MHz to optimize efficiency and external component size.

The LT3496 supports 3000:1 dimming control on each channel. Each of the three regulators is independently operated by that channel’s PWM signal. The PWM feature allows precise adjustment of the color mixing or dimming ratio of the LED source. Each of the three channels has a built-in gate driver to drive an external LED-disconnect P-channel MOSFET, allowing high dimming range. The output current range of each channel of the LT3496 is programmed with an external sense resistor.
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