| 摘要 |
PURPOSE:To reduce a ripple and to increase response speed by storing a frequency/voltage conversion output in a 2nd capacitor and correcting the charging voltage of the capacitor at every period of an input signal frequency according to the charging/discharging state of a 1st capacitor. CONSTITUTION:An input signal IN is supplied to a triangular wave generating circuit 19 through a differentiating circuit 11 and a signal input detecting circuit 16 and a capacitor CB is charged and discharged to generate a triangular wave; and a differentiating circuit 18 generates differentials pulses corresponding to rise-to-fall return points of the triangular wave. The output of the circuits 11 and 18 are supplied to a circuit 16 to detect whether or not there is the input signal and the outputs of the circuit 16 and 19 are supplied to an acceleration/deceleration detecting circuit 15 to detect the acceleration and deceleration state of the frequency of the signal IN. The output of the circuit 26 is supplied to a charging/ discharging control circuit 34 and a voltage/current converting circuit 35; and the circuit 34 charges and discharge the capacitor CB by the circuit 26 and the circuit 35 converts the charging/discharging voltage of a capacitor CA under the control of the circuit 34. The charging voltage VA of the capacitor CA is so controlled that the leading of the signal IN coincides with the passing point of a voltage VE being charged in the capacitor CB; and the ripple of the output voltage is reduced and acceleration/deceleration response is improved.
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