Automatic & Fail-Safe Biasing of GaN Transistors

GaN HEMT transistors are depletion mode devices and so require a negative voltage for the gate and a positive voltage for the drain. It is sometimes inconvenient to have to provide both positive and negative supply voltages. Also, since they are depletion mode devices IT IS CRITICALLY IMPORTANT TO SUPPLY A NEGATIVE VOLTAGE TO THE GATE BEFORE ANY POSITIVE VOLTAGE IS APPLIED TO THE DRAIN as otherwise the transistor will draw its maximum possible drain current from the supply which is likely to lead to excessive thermal dissipation and the device burning out. For these reasons Integra Technologies has developed a fully automatic and fail-safe bias circuit for its GaN transistors that only requires a single positive voltage power supply.