A PROTECTION CIRCUIT FOR A NORMALLY-ON (DEPLETION MODE) JFET AND THE POWER APPARATUS

摘要

PURPOSE: A circuit for protecting a depletion JEFT(Junction Field Effect Transistor) and a power supply unit using the same are provided to generate a negative voltage for switching operation of JFET by including a regulator. CONSTITUTION: A filter(310) remove a noise element of an input AC power(300). A bridge diode(320) rectifies an AC signal to a DC voltage. Two DC link capacitors(330,340) are charged with the DC voltage. A regulator protects the JFET from a rush current. The regulator generates the negative voltage for driving the JFET. A gate control signal generator generates a control signal for switching the JFET.