Uni SMPS 300W

[Acca]

Here's my smps,all parts is from at/atx pc psu.I'll tested it,and works great.If it don't start to oscillate,reverse feedback windings (15k resistor goes on it).Feedback transformer is original EE16/19,not rewounded.Output rectifier is on another board.Schematic and pictures:

 

[wally7856]

Very cleaver circuit, i would like to see a better schematic and an explanation of how it oscillates.

 

[Acca]

smps

Self oscillating,proportional base drive,feedback through 15k resistor is only for keep oscillations on because current is small.Instead 15k resistor you can use 470pF cap and 4k7 resistor in series.

 

[Acca]

What better?

 

[Acca]

Better schematic and test with tda7294:

 

[wally7856]

Thanks for the schematic! What transistors are you using, and did you measure the output and get 300 watts?

 

[Acca]

Transistors is any from pc psu,I measured more than 300W but,EE33 is for 300W max for continual operation.

 

[Acca]

Fullbridge,1kW

 

[wally7856]

Can you please re-do the 1kw jpg. It is to small and i can not read it.

 

[Acca]

Ok,here is it

 

[gloriel]

Ok,here is it
View attachment 3973

hi acca what size T2?? EI28 is enough??
thankyou

 

[wally7856]

Acca, thanks for the larger schematic. I have searched the Internet to try to find the design rules for your proportional drive self oscillating circuit, but only found vague references in schematics for CFL light bulbs. Do you have a publication or web site that explains how to design these circuits.

 

[Acca]

hi acca what size T2?? EI28 is enough??
thankyou

Yes,but for ~200-250W

 

[Acca]

Acca, thanks for the larger schematic. I have searched the Internet to try to find the design rules for your proportional drive self oscillating circuit, but only found vague references in schematics for CFL light bulbs. Do you have a publication or web site that explains how to design these circuits.

You can search only "proportional base drive",I don't have any site,I know this from PC PSU

 

[gloriel]

this is my set up. this smps work good.

 

[Acca]

Yes,it's work good

 

[gloriel]

hi acca,

for more power do you have any big bjt recomendation???

 

[Acca]

Use bjt with more current handling,or try fullbridge

 

[Acca]

hi acca what size T2?? EI28 is enough??
thankyou

Sorry,for T2 you can use ee19,I mean T1

 

[gloriel]

EE19 is gapped core.. it is usable as gdt???