| 摘要 |
PROBLEM TO BE SOLVED: To realize an amplifying circuit which is unlikely to be influenced by noise, drift, and the like, capable of amplifying minute signals, and operated by a single-polarity power supply. SOLUTION: An amplifier, operated by a single polarity power supply, in which each end voltage of a resistor inserted in a flow path of a detecting current is applied, and used for obtaining a prescribed gain from a ratio between an input-side arithmetic resistor and a feed-back side arithmetic resistor; a high-gain integrator connected from the output side to input side of the amplifier in a feed-back way, in which the deviation of the intermediate voltage of the power-supply voltage and an output voltage of the amplifier is entered; and a switch turned on during time of zero of the input signal of the amplifier for connecting or disconnecting the high-gain integrator are provided. Then, positive and negative input signals can be treated with the single-polarity power supply, so the circuit can be made simple, a minute signal voltage can be amplified with high accuracy, and also gain accuracy of the integrated amplifier can be made high. The shunt resistance value of the signal source can be made small, and generation of heat can be reduced, and thereby packaging becomes easy. In this way, integration with a gate driver for driving a switching element becomes possible. COPYRIGHT: (C)2005,JPO&NCIPI
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