CURRENT-TO-VOLTAGE CONVERSION CIRCUIT FOR PDIC EMPLOYING GAIN SWITCHING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a current-to-voltage conversion circuit for improving the speed of a photoelectric conversion device and frequency characteristics of an amplifier by improving a method for switching the gain of an amplifier circuit for a PDIC. SOLUTION: A photocurrent generated in the photoelectric conversion device such as a photodiode is transferred to an amplifier by means of current mirroring so as to raise a bias voltage to the photoelectric conversion device and enhance a response speed thereof. Further, the amount of a current generated in the photoelectric conversion device is adjusted by the control of a resistance ratio of a current mirror circuit. Therefore, a fixed feedback resistor can be used for the amplifier irrespective of operating modes, so as to enhance frequency characteristics of the amplifier. COPYRIGHT: (C)2005,JPO&NCIPI