A setting/resetting circuit and a magnetic sensing device employing the circuit

The invention provides a setting/resetting circuit and a magnetic sensing device employing the circuit. The setting/resetting circuit comprises a capacitor, a coil, four switch units and a control unit. The four switch units are electrically coupled to the coil. The control unit changes the current direction of the coil by switching the four switch units and further resets the magnetic moment direction of a magnetoresistive sensor in a magnetic sensing device. The control unit can also change the resistance and/or the ON time of an electrical path provided thereby by controlling the four switches, thus adjusting the current of the coil. Therefore, the setting/resetting circuit can be operated only with one capacitor and the capacitor can be used for stabilizing the potential of the supply voltage thereof. 本发明提出种设定/重设定电路及采用该电路的磁感测装置。设定/重设定电路包括有电容、线圈、四个开关单元及控制单元。上述四个开关单元均电性耦接上述线圈。控制单元用以透过切换上述四个开关单元来改变上述线圈的电流方向，进而重置磁感测装置中的磁阻传感器的磁矩方向。控制单元也可控制上述四个开关单元改变其所提供的电性路径的阻值大小及/或导通时间，藉以调整上述线圈的电流大小。据此，本发明的设定/重设定电路仅需使用个电容即可操作