Transistor with integrated turn-off slew rate control

Abstract

A circuit structure includes an enhancement mode transistor and a turn-off slew rate controller for automatically adding drain-source capacitance to the transistor when the transistor is transitioning to an off state. The added drain-source capacitance slows the turn-off slew rate (dV/dt_off) of the transistor without also increasing the turn-off energy loss (E_off). The slew rate controller can include: sensors connected to the drain region for sensing both the drain voltage and the slew rate, respectively; a logic circuit for generating and outputting an enable signal based on output voltages from the sensors; and a capacitance adder for adding to the drain-source capacitance only when the logic value of the enable signal indicates that the drain voltage is at or above a predetermined positive drain voltage level and the slew rate is positive.