| 摘要 |
PURPOSE:To perform gate switching at high voltage and to completely cut off a source and a drain, by constituting a switching circuit with a clock generator which starts an operation by a power source switching signal, a booster circuit which inputs the clock of the clock generator, and a register for power source switching which inputs a booster signal as a gate input. CONSTITUTION:A VCC represents a first power source voltage at a usual time, and a VPP a second power source voltage higher than the first power source voltage, and a VP and the inverse of VP the power source switching signals, however, when the signal VP changes from an L to an H, a signal VPH having the potential higher than that of the VPP is generated in the booster circuit 2 by using the clock (phi) being generated in the circuit 2. Afterwards, the signal VPH is impressed on the gate of a transistor M1 whose drain is connected to the VPP, or the power source VCC' of an internal circuit, thereby, the power source VCC' can be raised. Also, the gate of a transistor M2 whose drain is connected to the VCC and whose source is connected to VCC' is connected to the inverse of VP, and the power source VCC' is separated from the power source VCC at the time of switching the power source.
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