Hello,
I am having some problems with a single stage LED driver based on the UCC28811. I made a redesign of my customers existing design. The existing design is 12W, whereas the new design is for 24W.I attached the schematic.
The image shows the input voltage vs the input current. Red is the current.
Two things are different than with the original design.
1) the current spike at the zero crossing.
The original design does have a jump, but no spike.
2) the current spikes all over the input current
I cannot find where these come from. The spikes are synchronuous to the current spike that occurs when the MOSFET is switched on, but compared to the number of switching cycles they happen only occasionally. It seems that it is a combination of the switching spike and some other event.
I measured the signal at the EAOut pin. This does not show these spikes. The signal at the Vins pin does. But I am not sure whether this is the cause, or that the signal is just also affected.
Does anyone recognize this behaviour? What can be the cause? What can I do to solve it?
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