| 摘要 |
PURPOSE:To protect a device (FET) against breakdown by receiving interruption signals from a plurality of FET interruption control circuits and delivering outputs to other FET interruption control circuits. CONSTITUTION:Overvoltage state of one power supply 1 among a plurality of power supplies 1-3 is detected by a detection circuit 1 which delivers a detection signal 1 to an FET interruption control circuit 4 for interrupting power supply to an FET 10 by delivering an interruption signal 1. The interruption signal 1 is also received by a photocoupler 17 which delivers an output to other FET interruption control circuit 5 producing an interruption signal 2. A photocoupler 18 receiving the interruption signal 1 delivers an output to an FET interruption control circuit 6 producing an interruption signal 3. Consequently, power supply 2, 3 for the FETs 11, 12 is interrupted and each device, i.e., FET 10, 11, 12, is protected against breakdown. |
