Full bridge using 2 dual anode rectifiers

[Circuitbreaker]

Hi Guys,

was wondering , as I see some implementations of the full bridge rectification using soft recovery dual rectifiers with common cathode like the famous MUR3020 ...

I'm struggling to understand how that is possible when in full bridge implementation there would need to be both common cathode and common anode version of the rectifier.

would be great to have the schematics as well to understand it better.

thanks,

Efi

 

[Frank Berry]

For a full wave bridge, you would need one dual rectifier with a common cathode and one with a common anode.

 

[Circuitbreaker]

thanks Frank.

so what's the case with PSUs having 2 of those MURs with the same model?

 

[PRR]

You can use a dual rectifier as a single rectifier. Two of the same model plus a CT winding makes a full-wave rectifier. With less voltage loss than a FWB.

 

[Vovk Z]

MUR3060 is ultrafast but SUR3060 is soft recovery type, I guess.

 

[Circuitbreaker]

You can use a dual rectifier as a single rectifier. Two of the same model plus a CT winding makes a full-wave rectifier. With less voltage loss than a FWB.

that makes sense , however I do see two dual rectifiers in some designs. been trying to search for schematics but to no avail.

 

[mchambin]

Could this be using two independent center tap secondaries ?
This asks for an uncommon transformer.
This enables making a dual rail PSU ( +V Gnd -V ) from two identical independent single rail PSU.

 

[gorgon53]

You can use a dual rectifier as a single rectifier. Two of the same model plus a CT winding makes a full-wave rectifier. With less voltage loss than a FWB.

but no free lunch, transformer secondary winding losses are higher

 

[PRR]

but no free lunch, transformer secondary winding losses are higher

Don't know who expects a free lunch. The application here seems to be a high frequency switcher, which typically has low-Ohms windings and broad wave-peaks, thus low loss.

 

[gorgon53]

The question did not sound to me like someone would ask about full bridge rectification in a hf switcher. When someone talks about "famous" diodes it sounds to me more like a question from a audiophile, normal grid 50/60Hz transformers, "fast" diodes made famous by some guru. I may be wrong off course.

Anyway, that is why I wanted to him, and others like him, make clear that there is no free lunch.
For PRR and many others this is nothing new, but for people not knowing this:

Secondary winding losses are considerably lower if, instead of using 2 serial connected windings (that are idle at least half of the time) you put the same amount of copper working twice as long by feeding a full bridge.