| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a compact, light current sensor that can be operated by a single power supply and does not prevent sensor output from being saturated due to shortage in a supply voltage. <P>SOLUTION: The current sensor comprises a Hall element 3 arranged in the gap of a core in which secondary side output winding L2 is provided while a primary side current to be measured passes through the Hall element 3; and a differential amplification circuit 10 for negative feedback in which the output voltage is applied. The output current of the differential amplification circuit 10 for negative feedback is allowed to flow through the secondary side output winding L2 so that the output voltage of the Hall element 3 reaches zero, when the primary side current to be measured flows, thus controlling magnetic flux in the gap to zero. In this case, although a detection resistor RL is connected to the secondary side output winding L2 in series and the output current is converted to a sensor output voltage, the sensor output voltage can be obtained as a potential difference in reference to common ground, and the common ground potential is changed in reference to the power supply ground of a single power supply 5 corresponding to the following of the sensor output voltage to an output current flowing through the secondary side output winding L2. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
