Favorite part, Low VF diode, low leakage

[Klaus Kragelund]

Hi

I am working on a forward converter and are into optimizing the diode losses.

Sofar the BAT720 has proven fairly good, but would like to get even lower losses.

So, when the PIV is 20V, I found the DFLS130:

http://www.diodes.com/datasheets/ds30445.pdf

Has really low VF, but one gain seldom comes with a penalty. It has high leakage current at elevated temperatures.

Anyone got a hit for a nice part?

Thanks

Klaus

 

[Joerg]

Hi

I am working on a forward converter and are into optimizing the diode losses.

Sofar the BAT720 has proven fairly good, but would like to get even lower losses.

So, when the PIV is 20V, I found the DFLS130:

http://www.diodes.com/datasheets/ds30445.pdf

Has really low VF, but one gain seldom comes with a penalty. It has high leakage current at elevated temperatures.

Anyone got a hit for a nice part?

No chance to use a FET and control the gate for an active rectifier?
Even if that's only for 80-90% of the conduction time that has gotten me
out of a pickle a few times.

 

[Klaus Kragelund]

What's the output current and voltage?



If this a push-pull, transformer-coupled, CT secondary, 2-diode

rectifier driving a filter choke?

Forward converter, 2-diode driving output filer. Current is 40mA, PIV is 30V

I am running it quasi resonant

Regards

Klaus

 

[Klaus Kragelund]

No chance to use a FET and control the gate for an active rectifier?

Even if that's only for 80-90% of the conduction time that has gotten me

out of a pickle a few times.

Yes, I have tried with sync rectification, self driven. Increases efficiency by 1%. Trouble is at that low current the gate charge for the FET takes almost as much that is saved in lower loss from the FET RDSon versus diode.

Regards

Klaus

 

[Klaus Kragelund]

Yes, I have tried with sync rectification, self driven. Increases efficiency by 1%. Trouble is at that low current the gate charge for the FET takes almost as much that is saved in lower loss from the FET RDSon versus diode.

Also, using self driven sync FET, I cannot use cycle skipping to remove standby losses, since the FET gate in uncontrolled when the switching stops

Regards

Klaus