| 摘要 |
PURPOSE:To prevent power from being consumed wastefully when no current is outputted, by controlling the base circuit of a bipolar transistor consisting of a current source directly with a MOS transistor and a transfer gate. CONSTITUTION:Since the output of an inverter G1 goes to an 'H', and the output of an inverter G2 goes to an 'L' when the potential of an input terminal IN is at the 'L', the transfer gate T is turned ON, and also, an N-channel MOS transistor M1 is turned OFF. Therefore, a current output Io can be obtained at the collector of the bipolar transistor. Meanwhile, when the potential of the input terminal IN is at the 'H', the transfer gate T is turned OFF, adversely, and an almost insulated state is generated between a voltage source Vcs and the base of the bipolar transistor Qcs, and also, the N-channel MOS transistor M1 is turned ON, and the bipolar transistor Qcs is completely turned OFF, thereby, no current output can be obtained.
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