| 摘要 |
An objective of the present invention is to provide a differential circuit having a compensation function of an offset voltage. A sample-and-hold circuit including a transistor and a capacitor is connected to the differential circuit. The sample-and-hold circuit acquires a voltage for correcting the offset voltage of the differential circuit by charging or discharging the capacitor through sampling operation. Then, it holds the potential of the capacitor through holding operation. In normal operation of the differential circuit, the output potential of the differential circuit is corrected by the potential held by the capacitor. The transistor in the sample-and-hold circuit is preferable to use a transistor whose channel is formed using an oxide semiconductor. Since an oxide semiconductor transistor has extremely low leakage current, a change in the potential held in the capacitor of the sample-and-hold circuit may be suppressed. Accordingly, if the sampling operation is performed once, it is not necessary to perform the sampling operation before execution of a normal operation of the differential circuit. |
