| 摘要 |
PURPOSE:To attain the drive of a simple saturation type transistor (TR) switch by providing a differentiation circuit and a switch element so as to obtain an edge detection pulse such as leading or trailing edge of an input signal in a form of a positive potential pulse with respect to ground level. CONSTITUTION:When an input voltage V1 rises, it is given to a base of a TR Q31 via a resistor R12, the Q31 is turned on and an output voltage VO3 drops to 0V. Then the charging voltage of a capacitor C11 reaches 0.7V, then the TR Q11 is turned on to draw a base current of the TR Q31 to ground. The TR Q31 is turned off and the output voltage VO3 is restored to VH. A leading edge detection pulse is outputted for a period of t1 from the leading of the input voltage Vi till the turning-off of the TR Q11. When the voltage Vi descends, the TR Q11 is turned on, the TR Q21 is turned off and the TR Q31 is turned off and the input voltage Vi appears at an output terminal as it is via resistors R22, R31 and the output voltage VO3 reaches 0V. On the other hand, the voltage is given to the base of the TR Q31 via the resistor R12 and the TR Q31 is turned off. When the voltage across the C21 reaches 0.7V, the TR Q21 is turned on. The TR Q31 remains at the OFF state and the voltage 03 is restored to the VH. |
