BIAS CURRENT CONTROL METHOD FOR OPERATIONAL AMPLIFIER CIRCUIT, THE OPERATIONAL AMPLIFIER CIRCUIT, CURRENT CONTROL CIRCUIT AND SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an operational amplifier circuit, capable of suppressing the occurrence of operation defects caused by a process dispersion or the like, and of providing a high common-mode signal removal ratio. SOLUTION: In a control circuit 43, a first bias current I1b is generated by adding a current I2b of the same value as a second bias current I2a to a current I1a to flow to a first current source 53. Therefore, there is no time difference between the change time of the first bias current I1b and that of the second bias current I2a, and the fluctuation quantities (absolute values) of the respective bias currents I1b and I2a become equal. Thus, the control circuit 43 makes the total of the current values of the first and second bias currents I1b and I2a, which are to be supplied to first and second input differential couples 51 and 52, a constant value (=I) at all times.