UCC28051: UCC28051

Stuart Linzer

Intellectual 260 points

Part Number: UCC28051
Other Parts Discussed in Thread: TIDA-00701

In reference design TIDA-00701 the Bridge Rectifier power loss is calculated.

The power losses calculation uses average input current rather than rms input current. Why is the average current used?

Regards,

Stuart

over 2 years ago

0 Mike O' over 2 years ago

TI__Guru* 75905 points

Hello,

Diode losses are based on average current and not RMS. RMS calculations are used to calculate resistance losses so the calculation is correct.

Regards,

0 Stuart Linzer over 2 years ago in reply to Mike O'

Intellectual 260 points

Hi Mike,

Can you give more insight into why diode losses use average current? Mosfet losses use rms current but I assume that's due to Rds being a resistance.

0 Mike O' over 2 years ago in reply to Stuart Linzer

TI__Guru* 75905 points

Hello,

It is based on the diode being model as a voltage shunt. There are IV losses but not I^2*R losses. This is know for estimating power loss in diodes. However, there are models of diode that account for the impendence of the diode. If you would like to calculate the losses of that internal impendence then you would use the RMS currents.

Regards,

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UCC28051: UCC28051