The high side MOSFET becomes extremely hot when I try to run the half bridge, and the output does not seem right.
The PWM signals to Hin and Lin come from an Arduino – 47.5% duty cycle, dead time of 132ns, switching at 3.14kHz.
What could have been the problem?
- Is my deadtime too small? I tried increasing it to 40usec. and did not see a change.
- Is it the placement of ground right? Should it be moved from P1 to P2? If so, what should the polarities of C3 and C4 be?
- Should C1 and C2 be electrolytic or ceramic? (http://tahmidmc.blogspot.com/2013/01/using-high-low-side-driver-ir2110-with.html mentions that ceramic capacitors should go parallel to electrolytic capacitors).
- I am using 220uF, 250V capacitors for C3 and C4, could they be an issue as well?
In the picture below, the yellow wave form corresponds to the gate input of the high side switch, the blue waveform corresponds to the gate input of the low side switch and the purple waveform corresponds to the output across the output resistor Rload-1kohm.
Best Answer
You can't expect the bootstrapping circuit to work at such a low frequency with such low value bootstrap capacitors. In other words, you upper MOSFET gate drive signal runs out of steam and turns the upper MOSFET into a regular source follower dropping several volts across it.