How do you drive the gate of a MOSFET in an inverting buck-boost converter?

Question

I'm currently working on implementing a buck-boost converter for MPPT of a solar cell, the gate of the transistor is to be fed 0-3.3 V PWMlogic and I am planning on using a gate driver IC to combat the gate charge and shift the logic to appropriate voltage levels. However, the MOSFET source is exposed to negative voltage due to the inverting nature of the buck-boost topology.

In my case, for a certain irradiance level, the voltage of the panel at the maximum power point is ~16 V, at which the output voltage is brought to ~-20 V. I think using PMOS is part of the solution here, but finding a gate driver IC that can output negative bias is proving difficult; and I can't reference the gate to the output voltage since it is constantly subject to change. If there's something I've missed or misunderstood, please feel free to post. Any help would be appreciated.

^{simulate this circuit – Schematic created using CircuitLab}

Answer 1

However, the mosfet source is exposed to negative voltage due to the inverting nature of the buck-boost topology

In the configuration you have chosen, the internal body diode of the p-channel MOSFET will always be conducting current from the supply into the inductor = short circuit scenario.

Internal body diode: -

Image from What is the MOSFET body diode. This will make your circuit like this: -

If there's something I've missed or misunderstood, please feel free to post. Any help would be appreciated.

You could swap the positions of source and drain to get this configuration: -

Image from Inverting Switching Converter Design Equations.

This has got be be an easier way to drive the p-channel MOSFET.