Bidirectional blocking accumulation-mode trench power MOSFET

摘要

One or more diodes are integrated with a trenched gate accumulation-mode MOSFET to provide protection for the gate oxide layer. In a preferred embodiment, a first pair of diodes are formed in a series connection between the source and the gate of the MOSFET. A third diode may be added to provide a series diode pair between the drain and the gate of the MOSFET. A pair of accumulation-mode MOSFETs may be formed in a single chip to provide a push-pull halfbridge circuit, and a multiple-phase motor driver may be fabricated in two chips, with the high side MOSFETs being formed in one chip and the low side MOSFETs being formed in the other chip. The accumulation-mode MOSFET may be used as an AC switch by connecting its gate to a gate bias circuit which finds the lower of the source and drain voltages of the accumulation-mode MOSFET.