我们将在春节假期期间对网站进行维护,可能暂时无法访问,同时工程师回复将有所延迟,敬请谅解.

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关于DLP4500 LED驱动的工作原理问题

Other Parts Discussed in Thread: TPS54620

请教以下问题:

1,如图是green led driver的原理图,我的理解是R216左侧的LED_EN信号能控制Q17的Vgs从而控制led的亮灭,但是还没弄清楚通过调节LEDG_PWM的占空比怎么调节led的亮度?

2,测试发现U46的7脚VSENSE处电压稳定为0.8V,从LEDG_PWM出来的pwm波经R217和C272滤波后也基本变为直流,那led光源的阳极(ANODE)和阴极(CATHODE)之间的电压和电流是如何变化达到调节led光源亮度的?