| 摘要 |
PURPOSE:To accurately perform optical information communication by reducing the quantity of electric charge charged in a capacitor at the time of approach of respective voltage levels of an output voltage and an input signal voltage to each other. CONSTITUTION:A current Ia is supplied from a current supply source 22 to a capacitor 21 holding the peak voltage. A current adjusting circuit 23 switches a current Id1 based on relations between an input signal voltage Vin and an output voltage Vout to quickly discharge the electric charge charged in the capacitor 21. By the action of this circuit 23, the negative peak voltage of the voltage Vin is held in the capacitor 21 to perform the normal peak holding operation. Meanwhile, a current adjusting circuit 24 increases a discharge current Id2 as respective voltage levels of voltages Vin and Vout approach each other, that is, the level difference between respective voltage levels is reduced. Thus, an erroneous signal is not generated at the time of the absence of the signal to perform accurate optical information communication. |
