50V cap very hot

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my class d design...
the BTL output filter is butterworth 2nd order
as the 50V electrolytic cap 1uF parallel with the loading 4ohms is very hot

i want to change other high quality cap
so that the cap cannot easy get hot

does anyone can give me suggestion (what cap should be choose)?


my design : 15V Vcc to the FULL H-bridge(2 NMOS)

thanks
 
Hi,

Yeah I think tha'ts because of the higher ESR of the electrolytic cap, you can't use em for that, too much ripple current and they heat up.

"THE" cap to use I believe is a Wima MKT??

Or something like this should work
http://www.panasonic.com/industrial/components/pdf/abd0000ce24.pdf

Digikey has those.

Or any MKT, I think Wima's are sort of the "standard" for best sound though.

Hope that's some help.
Going to post your design? Sounds interesting, maybe someone can give you ideas for it too.

Whoa, I just read your post again and missed a few things, sorry I haven't had the coffee yet.

If all you have for now is electrolytics, at least use two of them, twice the value you're using now, dont' put them across the load but tie them to ground. By putting it across the load you're forcing current through it backwards and it is going to breakdown the oxide dielectric layer (out comes the smoke).

Regards,
Chris
 
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