CURRENT DETECTION CIRCUIT AND LIGHT RECEIVING DEVICE USING SAME, AND ELECTRONIC EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To provide a current detection circuit capable of accurately detecting a current flowing to a light receiving device.

SOLUTION: A first transistor Q1 is provided on the current path of a phototransistor 210. A second transistor Q2 constitutes a current mirror circuit with the first transistor Q1, and charges a charge capacitor Cchg whose potential at one end is fixed by multiplying a current flowing to the first transistor Q1 by a predetermined coefficient. A switch for discharging SW4 is provided in parallel with the charge capacitor Cchg, and turned on for a predetermined period before the phototransistor 210 starts to receive light. A switch for masking SW3 is provided on the current path including the second transistor Q2 and the charge capacitor Cchg. The switch for masking SW3 is turned off for a predetermined period before the phototransistor 210 starts to receive the light.

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