TO-220 and other 3-pin dual diode modules: common cathode?

[eccerr0r]

I was looking at a bunch of my TO-220 dual diode output rectifiers, and a vast majority seems to be common cathode - which would be perfect for making forward and push pull converters, and not too had to use both for flyback. But I wonder if anyone has seen many common anode devices, which probably would only be good for flyback?

I have this ~40W PSU that has extra component holes for extra outputs and was tracing how the unused positions are hooked up, and it would make sense only if this one TO-220 device was common anode (and the cathodes are shorted together externally for a flyback design). Looking at my parts bin, all of them are common cathode...

Are these really as uncommon as I think they are?

[budm]

Re: TO-220 and other 3-pin dual diode modules: common cathode?

The dual Diode are just that, it can be used as full wave rectifier set up, most SMPS use them as half-wave rectifier setup and just parallel the two diode together. You use Common Anode for the Negative out put. Common part.
https://cdn.badcaps-static.com/pdfs/...a57ada6ebd.pdf
http://www.onsemi.com/PowerSolutions...?id=MUR1620CTR

[eccerr0r]

Re: TO-220 and other 3-pin dual diode modules: common cathode?

Odd, of all the PSUs I've parted they were pretty much all CC... was thinking they didn't make CA - I was thinking the two diodes in series would be more popular than CA...

[budm]

Re: TO-220 and other 3-pin dual diode modules: common cathode?

Because most of them for the + out put, not negative out puts.
Here is simple +/- power supply:
http://www.circuitstoday.com/regulat...supply-circuit

[eccerr0r]

Re: TO-220 and other 3-pin dual diode modules: common cathode?

Exactly, CA would be best for negative outputs but since rarely do you want a negative output (about all that needs a negative output these days are possibly op amps, and usually even those use so little current and are satisfied by charge pumps) I thought manufacturers did away with CA completely to save money by reducing SKUs.

Oh well, I guess I need to look for a CA unit for this PSU or modify it to use a CC unit... Probably not worth sourcing a new one.