Out Put Diode Heating

Posted by: Pramod Natu on 06/27/2011

I designed 6 W Ps using Tiny switch III .
Recommended secondary diode heats up to much.(By PI Expert Software)
I have to use higher rating diode ,then it works fine.
can any one tell me the reason of heating.
thanks

Comments

How hot is the diode getting?
It is most likely because there is not enough heatsinking area for this diode. It can also be because a smaller diode was used.

I am using which is recommended by Pi expert 8.0
actually it is so hot that I cannot use it .it gets burnt out.

Then it indicates that there is not enough heatsinking in the layout.
Attach the PIXls file so I can take a look.

Attached *.Xls File

That it is too hot to touch is quite possible but it should not burn out, regardless of how much copper you have around it. Are you sure you have the right diode? That the polarity is correct? That the current is what you have designed it for?

Thanks
I am in the process of changing the lay out .

in the mean time I am using higher current rating diode in To220 pack
Regards

I'd still recommend to check this out a bit further.

Even if that diode was on all the time (which it is not) and even if the part is indeed 165C/W (while I find numbers closer to 50C/W) then 0.32A*0.7V*165C/W =37C rise above ambient. Even assuming the real situation is 2 times worse then a temp rise of 70 degrees is obviously too hot to touch but not enough to burn out the component.