Is this Half bridge converter circuit valid?

[CandleCookie]

I have some confusion about the half bridge converter. Can anyone help me to clarify it? Usually I saw the there are 4 diodes at the beginning of the circuit. What is the difference??

 

[FvM]

You mean the input rectifier? Your circuit is typically used for 115 V mains voltage. By adding two diodes and a switch, you get a selectable 115/230 V input SMPS, with fixed 300 V bus voltage. It uses a 4-diode bridge rectifier for 230 V and the 2-diode doubler for 115 V. Small SMPS are often wide range 100 - 240 VAC, using a bridge rectifier and a varying bus voltage, but the efficiency is lower than with a fixed bus voltage.

 

[CandleCookie]

Yes. I mean will this circuit works with AC voltage and convert to DC voltage. I'm using 110Vpeak as the voltage source.

Your circuit is typically used for 115 V mains voltage.

115V is Vpeak or Vrms?

By adding two diodes and a switch, you get a selectable 115/230 V input SMPS, with fixed 300 V bus voltage.

How to get the selection and how you obtain 300V bus voltage? 300V bus voltage is the output dc?

 

[FvM]

115V is Vpeak or Vrms?

115 VAC is a standard voltage in many countries, I don't think that 110 Vpeak is used anywhere. But I was just describing a typical usage of the circuit. You can use it with any voltage level you like to.

How to get the selection.

Compare the 2- and 4-diode circuits you have. Simply the connection to the capacitor midpoint is switched off.

 

[CandleCookie]

Yes. I'm just trying a certain voltage input. So, this circuit is certainly valid?
For getting the c1 and c2 values, the formula is c1=c2= current/(ripple voltage x frequency). The frequency here is it the input voltage frequency and not mosfet switching frequency?
Since the discharging for C1 and C2 is equal to charging of Cs, (C1xripple voltage1)=(Csxripple voltage). Can it be derived by this way? I can't find a circuit exactly same as this. So I try to derive myself.