| 摘要 |
PROBLEM TO BE SOLVED: To obtain a conversion circuit which needs only small compensation capacitance and can be mounted for many circuits by providing a current mirror circuit that is configured to make current caused to flow to 1st and 2nd current path sequence equal, etc. SOLUTION: This circuit is provided with an input terminal, which inputs an input current for being detected and a current mirror circuit which has 1st and 2nd current path sequence and makes current caused to flow to the 1st and 2nd current path sequence equal, etc. In the conversion, current from a photodiode is inputted the emitter side of an input base ground transistor Q1 through the input terminal. The current of the photodiode caused to flow from the input terminal is amplified by the current mirror circuit consisting of transistors Q2 to Q4 and resistance R2 to R4 and converted into a voltage by an output resistance R7. In such a case, because the resistance R2 and R3 have almost the equal resistance values to make current caused to flow to the transistors Q1 and Q2 equal to a current mirror current caused to flow to the transistors Q3 and Q9.
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