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110V output SMPS

Atul Bhakay37820
Prodigy 40 points

I want to design an universal input (85V to 265VAC) and 110V / 1 Amp output SMPS.

Kindly suggest suitable design.

Also what points to be considered while designing for such high output voltage ? Reflected voltage - ideaaly how much should it be ?

 

Regards

Atul Bhakay

  • Anonymous
    0 Anonymous

    Hi Atul,

    1. For such high input voltage variation, it will be very costly  and inefficient to design a DC-DC stage without using a voltage doubler at input.

    2. By voltage doubler circuit, I mean whenever you connect your supply to 110 V, the doubler circuit at the input will convert it to 220 V at the DC-DC stage. So you are basically left with designing DC-DC stage for 230 V input (10% tol). See this : http://edn.com/design/analog/4368346/Circuit-provides-universal-ac-input-voltage-adapter

    3.  For offline supplies , it is recommended to go for isolated design. Flyback seems the best option. 

    4. if you are designing PCB board, keep in mind of the proper isolation between primary and secondary side.  You can make cut-out on the board if you want.  

    5. In your case , since the output current is 1 A,  you can go for DCM flyback. 

    6. Reflected voltage choice depends on how much higher rating mosfet you want to choose. A higher reflected voltage means a higher stress on the mosfet. First choose a mosfet --> reflected voltage --.> turns ratio . 

    7. For isolation, you can use optocoupler  ( for secondary side voltage feedback) or else a transformer with Auxiliary winding . But it depends on which IC you are using for control.

    I am sure you will find a lot of designs online for DCM flyback. Good luck.

    -Ajit