| 摘要 |
PURPOSE:To enhance the control accuracy of load voltage by comparing a detected voltage corresponding to the absolute value of load voltage with a capacitor voltage and then charging/discharging a capacitor such that both voltages match each other thereby detecting the load voltage quickly and accurately. CONSTITUTION:A diode bridge DB takes out higher one-of potentials at points A and B through point D whereas takes out the lower one through point C and then a differential amplifier circuit comprising an operational amplifier 9 and resistors R11, R12, R21, R22 takes out the differential voltage through point E. A comparator 8 compares the potential at point E with that at point F and if the potential of a capacitor C2 is lower, a controlled current source 10 is operated to charge the capacitor C2 otherwise a controlled current source 11 is operated to discharge the capacitor C2. The operation is prohibited for a predetermined time synchronising with reversion of rectangular waveform through a monostable multivibrator 6 operating synchronously with the oscillation output from a low frequency oscillator 2. According to the constitution, a voltage corresponding to load voltage can be outputted through a buffer amplifier 13. |
