| 摘要 |
PROBLEM TO BE SOLVED: To apparently reduce a current-detecting resistor and to assure a high speed operation when a power is applied by providing two sets of resistor groups having equal resistance value ratios and an operational amplifier for supplying an output responsive to a voltage difference of an output side. SOLUTION: A current detector 4 has resistors 4r, 45, 43 and 42 groups connected in series, and an operational amplifier 41 for supplying an output responsive to a voltage difference between a connector of the resistors 44, 45 and a connector of the resistors 43, 43 to a connector of the resistors 45, 43. A resistance value ratio of the resistors 44, 45 and a resistance value ratio of the resistors 42, 43 are set to equal to each other. In the circuit 4, a voltage drop generated at the resistor 42 is compensated for a voltage drop of the resistor 44, and no voltage is generated between input terminals of the circuit 4. Positive and negative terminal voltages of the amplifier 41 become equal. As a result, a current flowing to a load 5 can be detected based on the voltage drop present at the resistors 44, 45.
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