DRIVER CIRCUIT OF FIELD EFFECT TRANSISTOR FOR DRIVING N-TYPE FET CONNECTED TO POSITIVE ELECTRODE OF SOURCE CIRCUIT

摘要

PURPOSE: Provided is a driver circuit of a field effect transistor(FET), which permits an N-type FET having more preferable characteristics than a P-type FET to be used in a protection circuit disposed at the positive electrode of a secondary battery with no delay in transformation into an off-state. CONSTITUTION: In the drive circuit of a field effect transistor, the drain of a first N-type FET(2) is connected to the positive electrode of a secondary battery(1), the source of a first FET(2) is connected with the source of a second FET(4), and the drain of the second FET is drawn as one part of output terminals. A first and a second switching devices(3,5) for turning on/off the first and second FETs are disposed between each gate of both FETs and the negative electrode of the secondary battery. A driver unit(7) is further connected to control the switching devices. Additionally, between the source connection of both FETs and each gate of both FETs, a voltage source for applying a gate potential higher than the source potential of the FETs is connected. The cathode of a diode(6) is connected to the negative electrode of the voltage source and the anode of the diode is connected to the negative electrode of the secondary battery. Further, the negative electrode of the secondary battery is drawn as the other part of output terminals.