Photo-detecting apparatus

摘要

The signal current corresponding to an incident light intensity is output from a photodiode, and the integrating circuit stores an electric charge according to the signal current and outputs a signal voltage corresponding to the amount of the stored electric charge. The first CDS circuit stores in the integrating capacitor an electric charge corresponding to a change in the signal voltage output from the integrating circuit. Similarly, the second circuit stores in the integrating capacitor an electric charge corresponding to a change in the signal voltage output from the integrating circuit. The difference calculation circuit determines a difference between the amount of charge stored in the integrating capacitor of the first CDS circuit and the amount of charge stored in the integrating capacitor of the second CDS circuit, and outputs a signal voltage corresponding to the difference.