Active power analog front-end based on a Wheatstone-type magnetoresistive sensor

In the proposed work a practical magnetoresistive wattmeter based on a commercial sensor is designed to measure active power at industrial frequencies. The electronic conditioning circuit uses differential blocks in order to preserve the sensor initial common mode rejection ratio. A 700 W power level has been reached with an uncertainty less than 1%. With few changes the proposed circuitry could be used in metering applications.