Operational amplifier circuit and offset correction circuit

摘要

PPROBLEM TO BE SOLVED: To provide an offset correction circuit capable of absorbing variation of offsets with a small circuit scale without the need of frequent refreshing, therby performing an offset correction. PSOLUTION: In an operational amplifier circuit 1, a switch element S1 is closed and a switch element S2 is opened. A latch circuit DL latches an output voltage of the operational amplifier 1a, performs a Q output corresponding to the latched output voltage, and a control circuit 2a inputs a signal s1 for offset correction to an offset adjustment input terminal OR of the operational amplifier 1a. The latch circuit DL further latches the output voltage subjected to offset correction by the operational amplifier 1a, and the signal s1 for offset correction is applied to fine adjustment in order to correct the remaining offset. Thus, the offset of the output voltage of the operational amplifier 1a is quantized by a correction amount weighted in accordance with what number time of the latch at that time, and the quantized offset is stored as a binary logical signal in the control circuit 2a. PCOPYRIGHT: (C)2007,JPO&INPIT