Help select topology 150-300W 0-50V

Ahmed Salama

Prodigy 130 points

Other Parts Discussed in Thread: PMP10215, LM5021, LM5039, PMP10110, UCC28951, PMP7391, UCC2894

Hello,

any topology reccomendation?

DCin = 390V

variable output voltage 0-50V

i was thinking about active flyback.

It should be ZVS / ZCS. For best efficiency. Thanks

over 5 years ago

0 Bernd Geck over 5 years ago

TI__Intellectual 2770 points

Hello Ahmed,

300W is quite a lot for a flyback topology, even a lot for a single ended forward topology.
Would not recommend push pull due to voltage stress at FETs and only half of the winding
is used.

A two switch forward or a hard switched half bridge is cost effective and suited for variable Vout.
PMP10215 shows a two switch forward using LM5021
PMP10110 shows a hard switched half bridge using LM5039

Both designs are close to your needs, best regards, Bernd

0 Ahmed Salama over 5 years ago in reply to Bernd Geck

Prodigy 130 points

Hello,

are there any other options with zvs? Thanks for your time. I apreciate it.

Have a nice day!

0 Bernd Geck over 5 years ago in reply to Ahmed Salama

TI__Intellectual 2770 points

Hello Ahmed,

300W is too much power for ACF; an interleaved ACF using two power stages is not that cost effective;
LLC can't handle the 0V to 50V output.
So if ZVS is a must go for a small PSFB using UCC28951 - but you buy for four FETs on primary side.

Best regards, Bernd

0 Ahmed Salama over 5 years ago in reply to Bernd Geck

Prodigy 130 points

Ok,

and 150W variant with active clamp forward is ok?

thanks

0 Bernd Geck over 5 years ago in reply to Ahmed Salama

TI__Intellectual 2770 points

Hello Ahmed,

please check i.e. PMP7391 using UCC2894, that's a 150W+ Active Clamp Forward powered out of PFC; BUT:
for variable output voltage 0..50V you won't get the 150W at 1V output voltage, this would result in 150A load current.

For selecting the windings ratio to achieve reasonable duty cycle you need to watch the drain voltage of primary FET;
to use a 800V or 900V FET duty needs to be a bit smaller. Please verify attached PDF.

Best regards, Bernd

ACF_Ahmed.pdf

Power management

Power management forum

Help select topology 150-300W 0-50V