| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a reliable current sensor which can accurately measure a current even when a magnetic core with a certain degree of residual magnetization is used. <P>SOLUTION: The current sensor is a magnetic balance type current sensor in which a hole element 3 is arranged in a gap provided on a toroidal magnetic core on which a coil L1 is wound around with a certain number of winding, and a current path in which a current to be measured flows is provided to go through the inside of the toroidal magnetic core. A magnetic flux generated at the toroidal magnetic core due to the current to be measured is detected by the hole element 3, and the output detected by the hole element 3 is amplified by a sensor circuit. The magnetic flux due to the current to be measured is neutralized by a negative feedback current flowing in the coil L1. The amount of the current to be measured is calculated from the amount of the negative feedback current of the coil L1. In addition, the current sensor comprises a reset circuit part 10 which makes to flow a bias current in a coil L1 in one direction while a power source voltage of the sensor circuit does not achieve a predetermined voltage when comparing the power source voltage and the predetermined voltage. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
