POWER SWITCHING CELL WITH NORMALLY CONDUCTING FIELD-EFFECT TRANSISTORS

摘要

A power switching cell with normally on field-effect transistors comprises a current switch receiving the control input signal over an activation input and a power transistor for switching a high voltage VDD applied to its drain, to its source that is connected to the output port of the cell. The control of the gate of the power transistor whose source is floating, according to the input signal, is provided by a self-biasing circuit connected between its gate and source. The current switch is connected between the self-biasing circuit and a zero or negative reference voltage. The self-biasing circuit comprises a transistor whose source or drain is connected to the gate or source of the power transistor. The gate of this transistor is biased by a resistor connected between its gate and source, and between the current switch and the source. The transistors are HEMT transistors using GaN or AsGa technology.

主权项

1. A power switching cell comprising:
an input port capable of receiving a switching control signal which is referenced to a general ground of the cell, constituting a non-isolated control of the cell; a normally on field-effect power transistor having a drain capable of receiving a positive supply voltage that is defined with respect to a ground at zero reference potential in order to apply it to an output port, and a source connected to the output port; a self-biasing circuit for biasing a gate of the power transistor; and a current switch electrically connected between the self-biasing circuit and a negative or zero reference potential, a switching control input of which is connected to the input port, and configured so that, on activation by said switching control signal, said current switch electrically connects the negative or zero reference potential to the self-biasing circuit, wherein the self-biasing circuit comprises:
a normally on field-effect transistor having a drain connected to the source of the power transistor and a source connected to the gate of the power transistor;a self-biasing resistor for biasing a gate of the transistor of the self-biasing circuit, which resistor is connected between the gate and the source of said self-biasing transistor; and in series between the current switch and the source of said self-biasing transistor.