| 摘要 |
The semiconductor circuit includes a voltage-controlled semiconductor device (N)N, the resistance value of which is controllable with a high voltage, the drain terminal of the N can be connected to the gate terminal (control terminal) of an output semiconductor device (N<SUB>O</SUB>) via a resistor (R) or to a last output stage of the driver circuit, the source terminal of the N is connected to the emitter terminal of the N<SUB>O</SUB>, and the gate terminal of the N is connected to the collector terminal, which is the output terminal, of the N<SUB>O</SUB>. When the input terminal of the semiconductor circuit is at the Hi-level, the N<SUB>O </SUB>OFF. By connecting the output terminal of the N<SUB>O </SUB>to the high-potential-side of a high-voltage circuit disposed separately and the negative electrode of a control power supply (VDD) to the low-potential-side of the high-voltage circuit in the state, in which the N<SUB>O </SUB>is OFF, a desired high voltage is applied between the collector and emitter of the N<SUB>O</SUB>. Since a p-channel MOSFET (P<SUB>D</SUB>) is turned ON as the input terminal potential is changed over to the Lo-level and the high voltage is still being applied to the output terminal of the N<SUB>O</SUB>, the N is turned ON and the N<SUB>O </SUB>is brought into the ON-state, in which the current driving ability of the N<SUB>O </SUB>is low. The semiconductor circuit can protect the devices from an over voltage with a simple circuit configuration.
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