Favorite part, Low VF diode, low leakage

losses.

leakage current at elevated temperatures.

What's the output current and voltage?

If this a push-pull, transformer-coupled, CT secondary, 2-diode rectifier driving a filter choke?

losses.

leakage current at elevated temperatures.

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.

losses.

leakage current at elevated temperatures.

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

I am running it quasi resonant

Regards

Klaus

losses.

losses.

leakage current at elevated temperatures.

Yes, I have tried with sync rectification, self driven. Increases efficiency by

Regards

Klaus

losses.

losses.

leakage current at elevated temperatures.

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

On a sunny day (Thu, 4 Oct 2012 16:01:59 -0700 (PDT)) it happened Klaus Kragelund wrote in :

losses.

leakage current at elevated temperatures.

Sometimes to really get a low drop, synchrounous rectification with a low RdsON MOSFET is used. All schotkeys are temperature sensitive, their reverse current is high at high temperatures.

You need to specify max current to be able to find a diode, or cool it with a heatsink.

Go looking for a Schottky with a lower forward current rating. Area goes with current rating, reverse current goes with area...

You'll need to juggle forward drop vs. reverse current: pay attention.

Look for a smaller FET! At 40mA, you've got a long way (down) to go.