| 摘要 |
PURPOSE:To apply level shift corresponding to the gain of a differential amplifier by providing the differential amplifier for level shift using a bias of a constant current source of the differential amplifier as a noninverting input and using the inverting/ noninverting output of the level shift differential amplifier so as to control the shift of the level shift circuit connected to the input/output section of the differential amplifier for signal amplification. CONSTITUTION:In decreasing the value of a variable resistor 11, a current flowing to a constant current source is decreased and the gain of a differential amplifier is decreased, the collector potential of a transistor (TR) 7 is increased, the potential of an output signal terminal 27 and when the potential rise is large, the TR of the circuit connected to the next stage is saturated. Thus, when the gain of the differential amplifier is increased and the collector potential of the TR 7 is decreased, the input potential of the differential amplifier is shifted toward the low potential side, and when the gain of the differential amplifier is reduced conversely and the collector potential of the TR 7 rises, the potential at the output signal terminal 27 is shifted toward the low potential. Thus, the TR 7 or the TR of the circuit connected to the next stage is prevented from being saturated.
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