I have designed a led driver based on the UCC28810EVM-001. The schematic is the same with a few modifications for Output voltage=24V and the current is 3.5A. The triac decoder from the secondary side was removed.
Without any triac connected, the power supply works perfect in both modes: CC and CV. Delivers 80W with good efficiency and amazing PFC.
This is a great solution for LED drivers, I wish that TI could see the opportunity here and provide more support. Thank you Lisa Dinwoodie for posting the mathcad calculation - really helpful!.
My problem starts when I connect the triac dimmer (Leading edge) into the circuit.
Without dimming - the triac misfire on low loads (around 0.5-1A output current). Once I start dimming and pass a certain angle, the triac acts normal on low end.
In example: If I connect a 3A load on the output the dimmer works perfect on all range. If I connect a 700mA load on the output the triac misfire on high end (no dimming) and acts normally when the angle exceeds 90 deg.
I have tried several dimmers but the behavior is the same.
Any suggestions? ideas?