Reverse recovery time of Schottky diodes

om 20V, north of 100 watts. Since this can cause grief with core losses it has to run continuous mode. So I need a diode with no or hardly any reverse recovery time. Now that we have 200V Schottkies here is the puzzler.

tten for a Schottky. There may be a PN guard ring that conducts up there, a nd will have reverse recovery. I've seen that happen, and it can get ugly.

ime

why Trr numbers are published at very low forward current conditions (like

10 mA on a >1 A diode)". It's usually published at an amp or more. Still pe ak current in a bost converter with a 5:1 to 10:1 step-up ratio is several times the rated average current and things could get ugly up there.

them I realistically get only one shot.

diodes have it. All you'd be doing is scale down the effect and then, by paralleling, scale it back up again. I don't want to hear your complaining. I have to design a boost converter that makes 5000 volts.

ility testing. The client engineers called it "the death machine" because o f all the warnings and skull & bones on it. Later, the agency compliance gu y walks in to witness the tests. I turn on the unit ... *TUNGGGG* ... oooouuuuiiiieeee .... guy rolls his chair all the way to the other end of the room. I had placed a big easel in the central hallway, urging everyone to back-up frequently because of electrical stress tests that day. After xx runs the PBX phone system quit working, shortly afterwards so meone hollered "HEY, my computer just froze up!"

board that they know (or should know) has a max 5 volt supply.

They probably know that you can get a nasty - thermal - burn from some of t he parts that dissipate enthusiastically.

The processors in my computer run at a lot less than 5V and the package spo rts a huge heat sink ...

--
Bill Sloman, Sydney
Reply to
Bill Sloman
Loading thread data ...

The Wikipedia article seemed to suggest that if you can keep the forward drop low enough to not turn on the PN guard ring that you'd be OK.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com
Reply to
Tim Wescott

Right, but realistically in a boost converter with a fairly odd VIN/VOUT ratio like 1:10 the Schottky will go towards 1V for Vf. I don't see a chance for the guard ring not to come on.

Unless I sign an executive order prohibiting PN guard rings to conduct current or any other shady business but for that I'd have to be president :-)

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

So does trr, and even more so, except that this other heat is in the switcher FET. If the switcher FET burns 8W less and Vf causes a 4W increase in dissipation the net improvement is still 4W.

Well, sure, do you have a suggestion?

--
Regards, Joerg 

http://www.analogconsultants.com/
Reply to
Joerg

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.