| 摘要 |
PURPOSE:To detect properly the on/off state of a main current even when a main current switch is in any operating potential to a control power supply by detecting the on/off state of the main current by a current flowing respectively into the 1st detection terminal or not of the 2nd detection termonal. CONSTITUTION:When a PNPN switch 1 is in the on-state and a potential of an anode terminal A is higher than an earth potential of the control side, the 1st detection transistor (TR) Q4 is active and the on-detection current flows from the 1st detection terminal C1. When a potential of a cathode terminal K is lower than the control power supply V2, the 2nd detection TR Q5 is active and the ON-detection current flows to the 2nd detection terminal C2. The flowing current from the 1st and 2nd detection terminals C1, C2 acts like flowing itself to the sensing resistor R3 and the on/off state of the PNPN switch 1 is detected depending on the presence of the current flowing to the sensing resistor R3.
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