I am planning to build a circuit that could convert a DC voltage (i.e. 18V) to an AC voltage with frequency f=1kHz and Vpp=36V. Here is my schematic in Orcad Capture Lite. The main idea is to use an H-bridge with 4 MOSFET and turn them on/off by applying specific PWM wave on the gate. So that the output between A and B will be an AC voltage.
- I use 2 N-channel MOSFET at the low end(IRF3205), and 2 P-channel MOSFET(IRF4905) at the high end. Also, there are two 2N2222 BJT to provide the gate voltage of the high end.
- V2 and V3 are PWM signals which are out of phase and with 20us overlap. (see waveform below.)
When I run the PSpice Simulation, the results are shown in the figure. The top one is the current of the V1 source. The bottom one is the voltage between A and B V_ab, and source-gate voltage of M5 Vsg.
The problem appears at the time of 0.5ms, at this time both P-MOS and N-MOS are turned on and causing large short current.
How to address this issue?
I increase the overlap time of both PWM from 20us to 100us. The result is followed. The large current happens when the rising edge of any PWM wave. Look closely at the V_SG of M5 (yellow curve), the value of V_SG will have a spike even it was at a low level. Is it because of the parasite capacitance?
Or someone has a better idea?