I try to build a simple DC to DC buck circuit, but I can't get a correct result.

Hi,

I have built a buck convertor circuit in Pspice for TI which is shown in below:

R3 is 33 ohm and R4 is 1K

But I got a wrong result, the simulation result is shown in below:

Although the mosfet has a correct PWM input, but the mosfet doesn't have a correct PWM output. So the buck convertor doesn't have a correct voltage output.

I try to remove the LC circuit in the convertor to test the mosfet, and I found that the mosfet can output a correct PWM output without LC circuit, but after I add the LC circuit, the mosfet output is incorrect.

I don't know what's wrong with it.

This link can download the simulation source file if you want:

https://gear-line.synology.me:4001/d/s/sjfOYLmpsWEVkuYjRHqDPrQdutWULnC2/...