UCC24612: SMPS Forward With Secondary Side Synchronous Rectification

gene glick72

Part Number: UCC24612
Other Parts Discussed in Thread: TPS28225

Design is for 500+ Watt offline forward SMPS. I want to run secondary side synchronous rectification. Frequency planned is 1 MHz, but not carved in stone. Is this part okay? The part selector says it is appropriate for forward, but in the data sheet it never mentions forward.

Any additional help is welcome. Either this device or perhaps another.

thanks in advance

over 5 years ago

0 Hong Huang over 5 years ago

TI__Guru 73915 points

Hi,

I assume your forward converter is with SR in CCM, right?

0 Hong Huang over 5 years ago in reply to Hong Huang

TI__Guru 73915 points

Also, where did you see UCC24612 can be used in forward converter? Can you provide that link for us to review?

0 gene glick72 over 5 years ago in reply to Hong Huang

Prodigy 100 points

0 gene glick72 over 5 years ago in reply to Hong Huang

Prodigy 100 points

No, not necessarily. Forward can go discontinuous. I have not decided yet how to setup the output inductance.

0 Hong Huang over 5 years ago in reply to gene glick72

TI__Guru 73915 points

Let's clear first. The freewheeling MOSFET current if it is in DCM, UCC24612 should be ok. But if it's in CCM, its switching frequency fsw should be < 100kHz. If > 100kHz, the associated power losses may become not acceptable.

For the forward MOSFET, when turn off it, it is always with current, which is equivalent to CCM turn off. So, again, fsw < 100kHz should be designed.

0 gene glick72 over 5 years ago in reply to Hong Huang

Prodigy 100 points

I guess this part won't work for me then.

Does TI have alternative parts for this application? SMPS forward, synchronous switching secondary, frequency >= 1 MHz?

0 Hong Huang over 5 years ago in reply to gene glick72

TI__Guru 73915 points

One possible option is TPS28225.

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UCC24612: SMPS Forward With Secondary Side Synchronous Rectification