| 摘要 |
PURPOSE:To improve the sensitivity, by using a plurality of differential amplifying circuits and making the hysteresis symmetrical to positive and negative input voltages. CONSTITUTION:In the differential amplifier circuits 6-8, two differemtial output terminals of the pre-stage and two input terminals of the post-stage are connected with capacitors 10, 11 and 12, 13 respectively. The output terminals of the amplifier circuit 8 of the final stage are connected to set and reset terminals of an FF9 via capacitors 14, 15 respectively. Further, switches 18-23 are provided between two input terminals of the amplifier circuits 7, 8 and the ground. An input terminal of the amplifier circuit 6 of the pre-stage is grounded via a switch 17 and an input signal Vin is given to the other input terminal via a switch 16. The switches 17-23, and the switch 16 are switched inversely with each other periodically. As a result, the hysteresis characteristics are symmetrical to the positive and negative input voltages, allowing to improve the sensitivity. |
