| 摘要 |
PURPOSE:To perform accurately photoelectric conversion even in a small region of the short-circuit current of a photodiode by setting the back gate of an MOS transistor to be switched to a potential within + or -1V of the cathode potential of the photodiode. CONSTITUTION:A diode 8 converts a short-circuit current generated in photodiodes 3, 4 into a voltage and sets the voltage of the back gates of N-ch MOS transistors 1-1, 1-2, 2-1, 2-2 to a potential within + or -1V of the cathode electrodes of the photodiodes 3, 4. Accordingly, the potential difference between the source, drain, channel of the transistors for forming a switch and the back gate becomes within + or -1V. Accordingly, the leakage current between the source, drain, channel of the transistors and the back gate can be set to almost zero. Therefore, substantially all the short-circuit currents generated in the photodiodes 3, 4 can be supplied to a diode 8 for voltage conversion. |
