Selecting MOSFET for Buck Converter Design

[UmaraDissa]

I have to design a buck converter to convert 230V AC to 210V DC. The output current has been specified as 25 mA.

I have searched all over the net, but I could not find a MOSFET which matched these specifications.

What I need to know is do I need to do any modification to the circuit so that the switching can be done using a MOSFET having different specifications or are there transistors which support 230V input, 210V output and Ids=25mA?

Newbie here, please help.

 

[jibon]

OK, Its really different kind of power supply, Buck converters are generally designed for DC-DC conversion. So you have to Rectify the 230V ac first, Because current is low, then Buck converter work at this kind of input voltage. IRF840, IRF830, IRF450 these kinds of MOSFETS could serve your purposes. But I have one question, From where the controller could have power to control its oscilation and switch the gate ?

 

[UmaraDissa]

OK, Its really different kind of power supply, Buck converters are generally designed for DC-DC conversion. So you have to Rectify the 230V ac first, Because current is low, then Buck converter work at this kind of input voltage. IRF840, IRF830, IRF450 these kinds of MOSFETS could serve your purposes. But I have one question, From where the controller could have power to control its oscilation and switch the gate ?

Thanks for the reply.

The MOSFETs that you have mentioned do meet my requirements, but I need a p-channel MOSFET. Do you know of any p-channel MOSFETs with similar characterstics?

I also am wondering how to switch the gate. I am supposed to convert the 230V AC supply to power the controller circuit, but I have no idea how to do that. Would seriously appreciate any ideas to achieve this.