Patent ID: 9041392
Filing Date: 2015-05-26
Classification: G01R

Abstract:
1. A current sensor comprising: a first current sensor unit configured to measure a target current to be measured flowing through a current wire and output a first sensor output; a second current sensor unit having substantially a same sensitivity as that of the first current sensor unit, the second current sensor unit being configured to output a second sensor output; a computation unit configured to output an addition value by adding the first and second sensor outputs and a difference value by calculating a difference between the first and second sensor outputs; a storage unit configured to store the addition value and the difference value output from the computation unit; and a determination processing unit configured to determine whether a malfunction has occurred or not based on the addition value and the difference value stored in the storage unit, wherein the determination processing unit determines an occurrence of malfunction if there is a correlation between the addition value and the difference value, wherein the determination processing unit is configured to compare an addition value calculated at a first timing with an addition value calculated at a second timing subsequent to the first timing so as to determine whether the addition value increases or decreases, compare a difference value calculated at the first timing with a difference value calculated at the second timing so as to determine whether the difference value increases or decreases, and identify a match if both of the addition value and the difference value increase or both of the addition value and the difference value decrease, while identifying a disparity if one of the addition value and the difference value increases and the other decreases, and wherein, after identifying the match or the disparity multiple times using a plurality of addition values and a plurality of difference values sequentially output from the computation unit, the determination processing unit determines that a malfunction has occurred if either the match or the disparity is consecutively identified a predetermined number of times.