help in designing flyback

[alaa6]

i am trying to design a power supply with wide range input 90-270AC by using flyback topolgy with current mode controller UC3842 and the output is 19VDC

can any one provide me with helpful sources or circuits or any suggestion

bset regards

 

[Tahmid]

Hi,
These diagrams may give you a start. They are the circuits for a 500W SMPS based on flyback, although flyback shouldn't be used for such high powers.

 

[alaa6]

thanx but this circuit will not work with me . i need the circuit without axuliary winding

 

[rajudp]

yes you can use it with axuliary winding. the winding help the R10 resistor (100 k 1 W ) . if you want to remove the winding bettwr go for more power resister or change to ucc3805 or other which work with low current

 

[Tahmid]

For auxilary power, instead of using transformer winding, you can use a capacitor-resistor dropper followed by a zener.
Like: