| 摘要 |
PURPOSE:To improve the offset control function by adding a circuit which compensate the offset to an offset compensating circuit consisting of an integration circuit and a switch. CONSTITUTION:An offset compensation circuit consists of an integration circuit containing an operational amplifier A14, a resistance R17 and a capacitor C11, a switch S13 and a resistance R18. This offset compensating circuit compensates the offset of an operational amplifier A13 but it is impossible to set said offset at a level lower than the offset voltage of the amplifier A14. Therefore an integration circuit consisting of an operational amplifier A20, a resistance R21 and a capacitor C20 is added together with an offset compensating circuit consisting of a switch S22 and a resistance R20 and a zero-voltage input circuit consisting of switches S20 and S21. This offset compensating circuit controls the offset voltage of the amplifier A14. Thus the offset control function is improved further.
|
