calculation of inductance in the buck converter

[selva murugesan]

hi frds

i have to design fly back buck converter circuit , which gives the output of 16v,12v,24v with 3 amps(all are separate).the input details is 95v-245v AC , 50/60hz.
in the buck converter , my main motto is to eliminate the primary transformer. so that i selected the rectification parts in 245v/1A level. actually i had finished the MOSFET selection also.

my problem is in the selection process of inductance. wh are the points to be considered in inductor selection?
i dont have any idea about the switching frequency related to inductance.

can any one help me to finish the buck converter circuit?

 

[smijesh]

You can’t eliminate the transformer from the circuit, it will leads to isolation problems. You must use transformer for 245V to 12V converters.

 

[selva murugesan]

You can’t eliminate the transformer from the circuit, it will leads to isolation problems. You must use transformer for 245V to 12V converters.

thanks smijesh

but i have to the make product in less weight and more comfortable. you might see the circuit diagram.

 

[smijesh]

As you said 16x3 + 12x3 + 24x3 = 156W, the converter should not be a small one or less weight. Please specify the actual requirement (Comfortable) .
1 Select high efferent low profile transformer.
2 Operating frequency increase as possible…ect .

 

[selva murugesan]

As you said 16x3 + 12x3 + 24x3 = 156W, the converter should not be a small one or less weight. Please specify the actual requirement (Comfortable) .
1 Select high efferent low profile transformer.
2 Operating frequency increase as possible…ect .

in the above figure ,it showed three different output voltages. but basically, three different buck converter. hopefully ,now you can understand my requirement.

which means just give way to find indctance for

(95-245)v AC, 50/60hz converts in to 16v/3A DC