| 摘要 |
PURPOSE:To decrease the effect of a stray capacitance exerted on the fluctuation in an analog voltage, by constituting a switch of two FETs of series connection, and applying an on-off pulse having a prescribed phase difference between a gate and a source of the FETs. CONSTITUTION:The transistor switch coupling a voltage holding capacitor C to a transformer TR selectively is constituted with the two FETs Q1, Q2 in series connection. The sources of the FETs Q1, Q2 are connected to a common source input terminal S and the gates are connected to a gate input terminal G via resistors r1, r2 respectively. The fluctuation in the analog voltage due to a transient charge/discharge current is prevented by adjusting the ratio of the resistors r1, r2. Further, an effective input impedance viewed from the voltage capacitor is increased by adjusting the transient charge/discharge current at on-off time. |
