Giant Magneto Resistive (GMR) effect based Current Sensing Technique for DC/DC Converters

Current sensing is one of the important function in a DC-DC Converter. It may be used for implementing current mode control or for achieving current sharing in a paralleled converters. Many current sensing schemes have been reported in literature, but they are either lossy or they require precise knowledge of the component value. In this paper a new giant magneto resistive (GMR) effect based sensor is used for low voltage, high current VRM type applications. Since the current sensing is based on magnetic field, thus the sensing accuracy depends upon the placement of sensor on the conductor. Various implementation issues while using such a sensor are studied and finally the performance of the sensor is studied on a 1 V / 15 A buck converter switching at 1 MHz.