Patent ID: 8587372

Claim:
A multi-input differential amplifying device, comprising: a differential amplifier including an inverting input terminal and a non-inverting input terminal; and an input portion configured to apply a first input voltage to a first input terminal which is one of the inverting input terminal and the non-inverting input terminal and apply a second input voltage to a second input terminal which is the other one of the inverting input terminal and the non-inverting input terminal, the first input voltage corresponding to first input signals including a plurality of input signals for the first input terminal, the second input voltage corresponding to a second input signal which is one input signal for the second input terminal, wherein: the input portion is configured to correct an offset voltage between the first input voltage and the second input voltage, the input portion comprises a plurality of input circuits corresponding to the plurality of first input signals, and each of the input circuits comprises: a first field-effect transistor having a source connected to the first input terminal and a gate to which a corresponding one of the first input signals is input; a second field-effect transistor having a source connected to the second input terminal and a gate to which the second input signal is input; and a back gate potential control circuit configured to generate a control voltage corresponding to a drain current of the first field-effect transistor and apply the generated control voltage to a back gate of the first field-effect transistor and a back gate of the second field-effect transistor.