Hello,
I'm a student designing a project. I have a PCB that I've designed, however, the power supply for it does not work. Below is a quick explanation of how it works and then the problem I am facing with it. I've also attached an annotated circuit diagram.
The power supply uses the TEA2208T and 4 mosfets for active rectification of the 120VAC.
From there the input of that is used by the lt3798 which does power factor correction and also modulates the flyback transformer in order to generate roughly 15vdc.
The main issue I am facing is that the lt3798 is not seeing any voltage at its Vin so it's not powering on. It uses high voltage to initially power itself and then "switches" over to the auxilarly transformer winding once that gets going. The high voltage goes through two resistors. For some reason I see voltage going in at the top of the resistor chain, I see half of that voltage in the middle of the resistors, but at the end of the chain I see nothing.
The other issue is minor in comparison and it involves the TEA2208T. For some reason the rectifier outputs 108VDC even though it's being fed 120VAC. I adjusted the EN/UVLO of the lt3798 to compensate, but the lt3798 still doesn't turn on.
Thanks
