Tool/software:
Hi,
I have the following circuit powering a string of LEDs, hooked up to a 3.3V microcontroller.
It's fed in 36V, and the nominal Vf of the LED string is around 30V.
I have the ADIM/HD pin always high, and the microcontroller is feeding the EN/PWM pin.
When PWM pin is set to HIGH, LEDs turn on at full brighness and everything behaves normally.
However, when the PWM pin is set to LOW, the LEDs don't fully turn off. Visually looking at the LEDs, they look like the remain at 10% brightness.
Feeding the PWM pin a 20kHz 50% duty cycle signal makes the LEDs run at around 50% brightness visually
I have checked the signal at the ADIM/HD and EN/PWM pins and they are as expected.
Why is this happening?
Thanks!
