| 摘要 |
PURPOSE:To eliminate the waste time of a system such as an inverter circuit by connecting a photocoupler turned on when the gate potential of a field effect transistor (TR) is lower then a source potential between a gate with a source being the drive circuit side of the field effect TR. CONSTITUTION:A gate resistor R1 is connected to the gate G of the field effect TR 1 and a main power supply 4 and a load 3 are connected in series between the gate and a source S. On the other hand, the positive side of an ON power source in an ON power supply 7 and an OFF power source 8 connected in series is connected to the power supply terminal 2a of the gate resistor R1 and the negative side of the OFF power source is connected to the power supply terminal 2a of the gate resistor R1. A diode 13 and a photocoupler 9 connecting a photocoupler input current limit resistor 14 in series are connected between the gate G and the source S of the field effect TR 1. A limit power supply 10 is connected to the output terminal 9a of the photocoupler 9 and an OFF detection signal line 12 detecting the OFF state of the field effect TR 1 is connected to an output terminal 9a.
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