Query on the reference design note for UCC28722

HPB

Other Parts Discussed in Thread: UCC28722

This refers to this application note using the UCC28722 to build a 5V, 2W universal input USB charger.

On page 4, while calculating the Iprms the equation lists Dmax however all other equations for RMS current calculations list Dmag. Is this equation correct?

over 9 years ago

0 Peter Meaney over 9 years ago

TI__Mastermind 31580 points

Hi Hrishikesh,

I will ask one of the systems enginner to review the application and respond to you.

Regards

Peter

0 Mike O' over 9 years ago in reply to Peter Meaney

TI__Guru* 85806 points

Hello Hrishikesh,

The secondary winding and the auxiliary winding RMS equations use Dmag. This is when these windings are delivering energy. The primary winding is conducting when the transformer is being energized. This RMS current is based on Dmax.

Regards,

0 HPB over 9 years ago in reply to Mike O'

Expert 1350 points

Thanks Peter and Mike. That helps.

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Query on the reference design note for UCC28722