buck regulator design

hi
i am making a buck regulator that convert a regulated 375 V DC acquired from 220 ac by a certain pfc circut to 50~175 VDC & i have used UC3844 current mode PWM ic level of output change by a potentiometer (volume) in feedback loop
losses in mosfet switch is high whatever i can,t compensate it by RL shunt snubber &it add many troublesome difficulty in circuit tr & tf of mosfet are lower than 100ns by transformer pulser
please guide me for lowering of mosfet losses
becuse of useing breadbord and not useing of cuurent transformer control circuit have many noise distortion how i can alliviate distortions is pcb enough what point i should consider in design of pcb

Can you post a schematic and some of the main component values? What's the switching frequency? Which mosfets? Which gate drivers? What voltage are you driving the gates? What's the max load current? Etc.

why not use the 220 Vac directly ? (after rectifying it)

What mosfet are you using?

Select one with a lower RdsOn to minimise losses is one way.....

Thunderchild said:

why not use the 220 Vac directly ? (after rectifying it)

Click to expand...

Presumably, he needs the power factor correction unit?

He probably also needs isolation.