| 摘要 |
<p>PROBLEM TO BE SOLVED: To inexpensively provide a magnetic balanced type current detector that can be operated by a single-pole power supply, is compact and accurately, and has a high response property. SOLUTION: A feedback coil 13 is provided at a ferromagnetic core, and at the same time a magnetism-sensing element 22 is arranged at a magnetic gap. Further, a signal-processing circuit for giving a feedback coil to a balancing current for cancelling magnetic flux in the gap is provided. The signal-processing circuit comprises a constant voltage circuit 17 for generating a constant voltage, a balanced current generation circuit 18 for generating a balanced current according to the output of the magnetism-sensing element based on the constant voltage, and a current-voltage conversion circuit 19 for converting the balanced current. The current-voltage conversion circuit comprises an amplifier 27, and a negative feedback resistor 28 that is connected between the inverted terminal and the output terminal of the amplifier. The balanced current is given to the inverted terminal of the amplifier. Additionally, the middle potential between a supply voltage VS+ and the ground GND is given to the non-inverted terminal of the amplifier.</p> |
