Charge Pump for P-Channel MOSFET

Question

Many N-Channel MOSFET drivers for high side switches and high speeds have charge pumps that can provide enough current at high voltage to drive the gate high and sink the current back out again. I have never seen this done for high side P-Channel MOSFETS. Are there any circuits or driver ICs that can generate charges 12 volts lower than the supply instead of 12 volts higher?

I have seen Infinion’s application note about high side P-Channels with IR2101, but it requires an external supply. I might as well not use a driver IC at that point.

Use a traco isolated module. – Andy aka Dec 12 '19 at 08:15 — Andy aka, Dec 12 '19 at 08:15
still hung up on trying to force the use of that PMOS, huh? – DKNguyen Dec 12 '19 at 14:35 — DKNguyen, Dec 12 '19 at 14:35

score 2 · Accepted Answer · answered Dec 12 '19 at 12:20

It would certainly be possible to use a charge pump to generate a negative gate voltage.

However, N-channel MOSFETs are cheaper/smaller than their P-channel equivalents. So when you have a charge pump anyway, you could modify it to generate a positive voltage instead, use an N-channel MOSFET, and save some cost/space.

In other words: a high-side P-channel MOSFET makes sense only if you can drive its gate directly and thus can use a simpler circuit.

Charge Pump for P-Channel MOSFET

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