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#1




Help needed with power losses calculation of a MOSFET's diode
Hello everyone, I'm currently trying to find out how much power will be lost during reverse recovery of a MOSFET's diode
( The effect of diode recovery http://www.apogeeweb.net/article/66.html). I'm using this paper for reference, https://www.fairchildsemi.com/applic...AN/AN6005.pdf the equation they end up with is P= Qrr*Vin*Freq_sw the problem is, for my application this gives an enormous number with the MOSFET I'm using. I have: Qrr = 1.9uC Vin = 380V Freq_sw = 100,000Hz which gives us a total power loss of 72.2W. My question is, does this seem right? I can't believe that almost 100 watts will be lost in just the reverse recovery process... My design output voltage is 300V using PWM. I figured I MIGHT have to multiply by the duty cycle (reverse recovery time * (frequency)) and this gives a much more reasonable answer, but I'm not sure if this is the correct way to go about it. Any help is greatly appreciated! 
#3




That is very helpful, thanks friend.

#4




This looks right if you use a normal diode.
You must use a FR diode, then your power loss will remain in the acceptable range 
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mosfet, power losse 
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