Hey, I’m currently trying to design a 12V/0.6A PoE power supply. For this, I’m using the MP8007 in Flyback and a transformer with 155uH, specifically the PoE 70P-12L from Coilcraft.
According to the calculation (Equation 8 on page 18), ILim should be 0.6A, which means
ILim = 100/R3 + Vl*0.18/L
=> 0.6A = 100/R3 + (-48V)*0.18/155µH
=> R3 = 152.5 kOhm.
Firstly, I’m encountering an issue where the simulation takes too long with the 152.5k ohm resistor. Additionally, my output current isn’t being effectively limited; when I use a smaller load resistor, for example, 10 mOhms, the output current exceeds approximately 1A.
Is there anything I’m overlooking? I’m still a bit confused about how the MOSFET is being driven and what frequencies should be generated here. Ideally, for my applications, 180 kHz would be perfect.
