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Kumar
Level 1
Level 1
First reply posted First question asked Welcome!

Hi Sir,

I need some help as I'm facing a MOSFET over heating problem. I'm working on a H bridge design, in which I want to use P(IRF4095) and N(IRF1010E) type MOSFE'S to change the polarity of a peltier. The problem now is that whenever I try to operate the H bridge with giving PWM input signals, the N(IRF1010E) type MOSFE'S temperature rocket climbs and it becomes even impossible to touch it. Mosfet is supposed to be able to handle 60Vand 84amps, and I am "only" using 12v, 15Amps.
So, is it normal for a power mosfet to get this hot?

  i have attached the circuit diagram.

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1 Solution
Neo_Qin
Moderator
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5 likes given 250 replies posted 250 sign-ins

Hi @Kumar ,

When you control a bridge arm(such as Q1+Q4 you mentioned), you can measure the Vds and Vgs of the low side switch (Q4). Compare the test results with the IRF1010E's output characteristic curve to determine whether it works in the linear region. Under normal conditions (saturation region), the Vgs should be 12V, and Vds should be only few tens of mV according to your appilication.

Take Kyocera's Peltier modules as an example. It takes at least 20s to achieve thermal stability. You have enough time to do the test, an ordinary multimeter is just OK, of course, oscilloscope is more recommended.

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4 Replies
Neo_Qin
Moderator
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5 likes given 250 replies posted 250 sign-ins

Hi @Kumar ,

According to your description, this is an unacceptable temperature rise. Q3/Q4 may be enter the linear region, or even pass the short-circuit current in a short time.

It is recommended that you use the oscilloscope to capture Vgs/Vds/Id information of any bridge arm and analyze them.

On the other hand, since the power MOSFET is not ideal, whether it is turned on or off, it needs a certain time, and an appropriate dead time should be added between the two drive signals.

Regards,

Neo

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Kumar
Level 1
Level 1
First reply posted First question asked Welcome!

thanks for your reply, currently i can't changed the polarity, i am testing for heat signal only (Q1 and Q4 - continuously on)  and (Q2 and Q4) not used, 

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Neo_Qin
Moderator
Moderator
Moderator
5 likes given 250 replies posted 250 sign-ins

Hi @Kumar ,

When you control a bridge arm(such as Q1+Q4 you mentioned), you can measure the Vds and Vgs of the low side switch (Q4). Compare the test results with the IRF1010E's output characteristic curve to determine whether it works in the linear region. Under normal conditions (saturation region), the Vgs should be 12V, and Vds should be only few tens of mV according to your appilication.

Take Kyocera's Peltier modules as an example. It takes at least 20s to achieve thermal stability. You have enough time to do the test, an ordinary multimeter is just OK, of course, oscilloscope is more recommended.

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Kumar
Level 1
Level 1
First reply posted First question asked Welcome!

ok sir 

 

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