UCC28634: Error in schematic design

Bernat F.

Part Number: UCC28634

Good morning sirs,

I am developing a Flyback using your component but although I followed the manual recommendations the resulting circuit is not delivering it's power.

It just enter in a infinite cycle of auto reset, with a periodicity of 1 second in which it turns on but immediately it turns off without any reason. (output consumption is really low)

Could anyone help me to review my schema in order to find what I am doing wrong?

Thanks for your help in advance.

over 2 years ago

0 Harish Ramakrishnan5 over 2 years ago

TI__Mastermind 22015 points

Hi Bernat,

Thanks for the query.

The restart of Vdd is normal in UCC28634 because there is a fault which needs to be addressed before controller starts switching.

Could you please share the pdf schematic, input output system specs and transformer design specs. like mag. inductance, turns ratiios etc. as it will help us assist better.

One suggestion from your schematic would be to make sure Vsense winding connections similar to datsheet page 54 (like use similar diodes like ES1D-13-F, BAV70 etc.).

The following threads can be useful to refer to in your debug process.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/545420/ucc2863x-fault-cause-codes/1990480?tisearch=e2e-sitesearch&keymatch=bernard#1990480

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/552925/ucc28631-not-starting-up/2023245?tisearch=e2e-sitesearch&keymatch=bernard#2023245

Thank you

Regards,

Harish

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UCC28634: Error in schematic design