| 摘要 |
PROBLEM TO BE SOLVED: To provide a light receiving amplifier capable of preventing linearity deterioration that occurs when current-voltage conversion efficiency is low in a light receiving amplifier that can change current-voltage conversion efficiency by changing a resistance value of a feedback resistance. SOLUTION: The amplifier includes a photodetector PD, a current amplification circuit 30 for outputting the current while amplifying output current of the photodetector PD, and a current-voltage conversion circuit 40 for converting the output current from the current amplification circuit 30 into voltage. The current-voltage amplification circuit 30 includes an operational amplifier 13, a feedback resistance Rgn1 connected between an inverted input terminal and an output terminal of the operational amplifier 13, a feedback resistance Rgn2 connected to the feedback resistance Rgn1 in parallel, a feedback resistance Rgp connected between a noninverted input terminal and the output terminal of the operational amplifier 13, and a transistor switch SW3 inserted between either the output terminal or the inverted input terminal of the operational amplifier 13 and the feedback resistance Rgn2. COPYRIGHT: (C)2008,JPO&INPIT
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