| 摘要 |
PURPOSE:To supply a specified value of pulse voltage of a correct ground level or the like, by generating an output voltage corresponding to a first voltage during a specified period when a voltage is changed in a pulse between a third voltage between first and second voltages and a fourth voltage biased in the opposite direction to the second voltage, not the first voltage. CONSTITUTION:An amplifier 20 receives first and second voltages V1 and V2 as working voltage, and a signal generation means 12 receives a third voltage V3 between the first and second voltages and a fourth voltage V4 biased in the opposite direction to the voltage V2, not the voltage V1, as input signal. When an output voltage C of the means 12 is a negative voltage V4, the output voltage D of the amplifier 10 tends to fall down a an negative level as the voltage V4 is below the working voltage V1 of the amplifier 10, but it will not be down below the ground voltage because the emitter of a transistor 26 is grounded. Thus, no current flows through a resistance 28 for current detection and so a negative power source terminal voltage V1 of an operational amplifier 14 is turned to the ground voltage. In other words, the saturation of the amplifier 10 enables the supply of a pulse voltage of correct ground level solely depending on the working voltage of the amplifier 10.
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