Effective Use of Miniature Multipoint Field-Based Current Sensors Without Magnetic Cores

A methodology for decoupling cross-coupled fields in compact current-sensor designs is presented. The compactness of the current sensor is made possible by using highly sensitive field detectors, such as giant magnetoresistive (GMR) technology, which offers galvanic isolation, small size (~ mm²), and high bandwidth (> 1 MHz). By using known geometric relations between the conductor geometries and locations of the field detectors, cross-coupled magnetic-field signals can be used to extract necessary current signals, as well as separate unknown disturbance fields. This methodology can also be used to simplify the magnetic biasing required of GMR field detectors, including decoupling of the temperature dependence of the biasing magnet. Moreover, the methodology can also be extended to estimate the temperature of the magnet to provide an extra temperature signal for thermal management algorithms.