| 摘要 |
PURPOSE:To control the rate of a negative feedback accurately, by providing a switch for a negative feedback path and controlling the switching time of this switch. CONSTITUTION:An input voltag is given to a terminal 10 and a control pulse with time ratio alpha is applied to a terminal 60. When an FET switch 151 is turned on, a capacitor 131 only exists in the feedback path and the input voltage is given to an operational amplifier 200. In this case, a current flows to the capacitor 131. When the FET switch 151 is turned off, the feedback path consists of a parallel circuit of the capacitor 131 and a resistor and no input voltage is given to the operational amplifier 200. In this case, a current flows from the capacitor 131 to a resistor 111. The circuit is stable when the time product between the flowing-in and flowing-out current of the capacitor 131 is equal, and the output voltag is controlled to (1-alpha)/alpha times the input voltage with the time ratio alpha. |
