Efficient Power Conversion Corporation

Suvankar Biswas

Michael Andrew De Rooij

David C Reusch

A cascaded synchronous bootstrap supply circuit with reduced voltage drop between the cascaded bootstrap capacitors by replacing bootstrap diodes with gallium nitride (GaN) transistors. GaN transistors have a much lower forward voltage drop than diodes, thus providing a cascaded gate driver bootstrap supply circuit with a reduced drop in bootstrap capacitor voltage, which is particularly important as the number of levels increases.

Low voltage drop cascaded synchronous bootstrap supply circuit

A fully integrated GaN driver comprising a digital logic signal inverter, a level shifter circuit, a UVLO circuit, an output buffer stage, and (optionally) a FET to be driven, all integrated in a single package. The level shifter circuit converts a ground reference 0-5 V digital signal at the input to a 0-10 V digital signal at the output. The output drive circuitry includes a high side GaN FET that is inverted compared to the low side GaN FET. The inverted high side GaN FET allows switch operation, rather than a source follower topology, thus providing a digital voltage to control the main FET being driven by the circuit.

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Blacksburg, VA, United States of America

Suvankar Biswas