| 摘要 |
PROBLEM TO BE SOLVED: To make actualizable a circuit which operates normally when powered on even at the time of light irradiation by making a photocurrent generated in a drain area more in a PMOS transistor than in an NMOS transistor, in a photoelectric transducer having a current mirror circuit. SOLUTION: In the current mirror constant current circuit 20 connected to the gates of PMOS transistors 13, 13', and 13" as constant-current loads, the drain area of a 1st PMOS transistor 2 is larger than that of a 1st NMOS transistor 4. Therefore, a light-generated hole generated in the drain area of the 1st PMOS transistor 2 is larger than a light-generated electron generated in the drain area of the 1st NMOS transistor 4 and the gate potentials of NMOS transistors 3 and 4 rise, so that the current mirror constant-current circuit 20 operates normally. The constant-current circuit 20 is not limited to a current mirror circuit and even when it is a circuit such as a differential amplifier circuit, malfunction under the influence of light irradiation can be prevented on condition that an element canceling the electron and positive hole of a light carrier generated at the PN junction part is available.
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