| 摘要 |
PURPOSE:To change the hysteresis width arbitrarily, by using a logical circuit element in which the threshold voltage is changed with the power supply voltage. CONSTITUTION:When the voltage of an input signal increases gradually from 0 volt, the output of an inverter 14 is at H level at first, and it is almost the power supply voltage Vcc. When the voltage of the input signal exceeds the threshold VTH (threshold at power supply voltage Vcc), the output is inverted to be at L level and becomes about 0 volt. Thus, the power supply voltage divided with resistors R1, R2 is applied to a positive power supply terminal C of the inverter 14. When the input signal voltage decreased gradually from around Vcc, since the output of the inverter 14 is at L level, and since the voltage at the power supply terminal C is a low voltage divided as above, the threshold voltage VTH' is lower than the VTH. Thus, when the input signal voltage is lower than the VTH', the output is inverted. |
