| 摘要 |
PURPOSE: To make it possible to secure stability and accuracy by providing a virtual ground circuit with an integrated partial circuit to be driven so as to supply a virtual ground having a half of power supply voltage. CONSTITUTION: Reference voltage is obtained by a circuit of resistors 43, 45, an amplifier 47 is connected to the circuit, buffer to an output V0 is obtained by the amplifier 47, and a temperature stabilizing current source is obtained by a bias circuit 39. The operational amplifier 47 acts as a gain '1' buffer and the output V0 is equal to the reference voltage generated from the resistor circuit and becomes the output of the virtual earth circuit. Since the amplifier 47 is used, high performance as the current inflow source and current outflow source of the virtual ground circuit can be obtained as a merit and the output impedance of the virtual ground circuit can be reduced. A reference current is generated by using the bias circuit 39 and an operation point in the circuit 39 is generated so as to be reflected to the remaining part of the circuit 39, so that an error item in virtual ground output voltage can be erased.
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