| 摘要 |
PURPOSE:To obtain a small-sized clamping circuit which operates stably with small power consumption without using any diode by performing errorless clamping operation through only a capacitive element, switch and amplifier. CONSTITUTION:When the degree of amplification of an operational amplifier 3 is sufficiently large, the voltage at a opposite-phase input terminal 4 is almost equal to a positive-phase input terminal voltage Ec. While an electronic switch 9 is open, an input signal 1 multiplied by the impedance ratio of the input capacitive element 2 (capacity value Ci) and a feedback capacitive element 8 (capacity value Cf), i.e. Ci/Cf appears at an output terminal 7. When the switch 9 is closed by being driven with a clamp pulse 10, the voltage at a terminal 7 is equalized to the voltage Ec at a terminal 5 forcibly. When the pulse 10 is ceased and the switch 9 is opened, the signal 1 is outputted from the point of time while its variation is multiplied by -Ci/Cf. |
