| 摘要 |
PURPOSE:To enable to switch the analog signal in the level up to the positive and negative power supply voltage without providing special power supply, by making equal the positive and negative power supply voltage of the switch drive circuit as the power supply voltage of the operational amplifier. CONSTITUTION:The operational amplifier 8 is used for the buffer circuit, and the signal in the level exceeding the positive and negative power supply voltage on the characteristics is sliced with the positive and negative power supply voltafes 10 and 11. Accordingly, it can be regarded as the ideal limiter which takes the positive and negative power supply voltage as the limit voltage. As a result, the switch element 6 having 0 volt of threshold voltage is used, and the same positive and negative power supply voltage of the switch drive circuit 9 outputting the positive and negative power supply voltage according to the positive and negative power supply voltage and the control signal of the operational amplifier 8 is used, allowing to switch the high level signal up to the positive and negative power supply voltage without signal leakage at switch closing. |
