Hi,
I followed PMP8803 to design a 48Vin to 12Vout/1A PD. Below is the SCH. It is almost the same as PMP8803, except MOSFET is CSD19533Q5A and one output cap is a 25V/10uF electrolytic capacitor
With 48V input, I found the MOS is very hot if Io>100mA. Below is when Io=100mA, CH2 is Vds, CH3 is CS(current sense). There is big noise on CS, and the MOSFET is hot.
Below is When Io=200mA. It works unstably and there is a lower frequency oscillation. It looks overcurrent comes periodically.
I've changed the gate resistor R10 from 10ohm to 0 and used a 150V MOS, but no any improvement.
Which measure can I do to locate the cause?
Thanks.