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UCC28086: Is it possible design? (input 12V, output 300V, 500mA)

Part Number: UCC28086
Other Parts Discussed in Thread: TL431

Hi Ti experts,

The customer requested the solution of the spec below.

Input : 12V

Output : 300V, 500mA

I couldn't find a solution in the TI reference design. so I used TI webench.

UCC28086D_300V_500mA.pdf

Please check the attached file. Is it possible design?

Thanks,

Downey Kim.

  • Hello Downey

    The UCC28086  would be a reasonable choice of controller but the Webench design won't work for a few reasons:

    A 300V output centre tap requires >> 600V reverse voltage rating for the rectifiers.

    the TL431 output error amplifier will be destroyed by the 300V output voltage.

    The solution would be to use a push pull primary circuit - Webench is correct for that part. The secondary should be a single winding with a full bridge rectifier secondary. This will halve the voltage stresses on the diodes. The losses associated with the additional Vf drop on the secondary won't be significant.

    Use a TL431 on the secondary as the error amplifier BUT you will need a separate dc voltage to supply its cathode current. That can be derived form a separate low power secondary winding on the transformer.

    Regards

    Colin