MOSFET shows higher power consumption than expected

[ihartavi]

Dear all,

I appreciate if somebody help me to find the rabbit lost in the hat. I designed a half wave rectifier by using a P-channel MOSFET instead of a rectifier diode. The target is efficiency. However, it is not the case with my design due to excessive power consumption of MOSFET in the simulation which is around 2W @ 2 A. I used ideal 4-pin device.

• Channel-A in the first picture is drain current which is measured across 0.01ohm resistor. The peak current while MOSFET is ON at steady state is 2.7 A
• Channel-B in the first picture is Vds which is 0.92 V while MOSFET is on at steady state
• Second picture shows Vout and Vg switching waveform. MOSFET is OFF when Vg is high (36 V)

Multisim shows 1.9 W power consumption in steady state. It should be determined by Rds(ON) in simulation. I cannot understand/explain why there is 919 mV drop on the MOSFET while it is ON.

Any idea?

Best regards!

[ikaiser]

Hello ihartavi,

Would you mind attaching your file here? Having your original schematics lowers the threshold for looking at it and trying to understand it.