problem of hearing lower power mosfet in single half bridge when used with ir2110

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Rinson

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problem of heating lower power mosfet in single half bridge when used with ir2110

Hi... i am building an inverter circuit using power mosfet st 8010 with IR2110 as gate driver ic.. i tested the circuit with only a single half bridge and it is working.. the output from IR2110 is fine and the gate to source switching voltage of both mosfets are as expected...

but the problem is .. the lower mosfet is getting abnormally heated.. while the upper one has no observable heating effect ...

can anyone tell me the reason and solution for this.. it is not the problem of the mosfet i double checked and connection of the two mosfets didn't seem having any problem...
 

Sounds like cross conduction. Low side is starting conduction before high side is releasing.

Look for a current spike during transitions. If you have series resistors in gate lines make sure they are not too large in resistance value based on input capacitance of MOSFET's used.
 
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    Rinson

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OK.. suppose it is cross conduction.. then why only the lower mosfet get heated ? why the upper mosfet is not getting heated ?
 

Where is your load returned? Is it to + supply, grounded or to - supply?

Also, what is your PWM frequency, % duty cycle, and buss voltage?
 

actually i was testing my circuit.. i was using only a single ir2110 ic and there was only a single half bridge associated . The dc bus voltage was 30 V and pwm frequency was one Khz and duty cycle is 50% .. i checked the the switching waveforms using cro .. i didn't see any crossing over ..

---------- Post added at 20:43 ---------- Previous post was at 20:28 ----------

sorry.. i think i didn't give complete details ...

i was checking the voltage out at the center of the half bridge ( in actual circuit there will be 3 such half bridges and 3 ir2110 )..
the reference was power ground
 

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