| 摘要 |
PURPOSE:To increase the sensitivity of detection with a simple constitution, by turning of FET if the output voltage of the level shift circuit is greater than the value of the input voltage of the second added by the threshold value and turning off it if lower, and by outputting the differential amplified voltage of the first and second input voltage. CONSTITUTION:The level shift circuit 1 consists of FET M1 making short circuit between the resistor R1 and gata and drain, and the input voltage V1 is fed to the source, and the inverter circuit 2 consists of the driving HET M2 applied by the output voltage of the circuit 1 and the load resistor R2, and the input voltage of V2 is fed to the source. Further, the voltage VA adding the voltage V1 with the thershold voltage Vth, the thershold value of FET M1 is appeared at the output A of the circuit 1. On the other hand, FETM2 of the circuit 2 is turned on if the voltage VA is greater than the voltage V2 added by the threshold voltage Vth and turned off if lower, causing the voltage VB amplifying the difference voltage between the voltage V1 and V2 at the output point B of the circuit 2. Thus, the detection sensitivity can be increased with a simple constitution. |
