An electrical system includes a first monolithic circuit. The first monolithic circuit may include a first magnetoresistive sensor operable to sense magnetic flux and produce an output signal relating to the sensed magnetic flux. The first magnetoresistive sensor may be positioned to sense first control flux generated by control current in one or more electrical conductors of the first monolithic integrated circuit. Additionally, the first magnetoresistive sensor may be positioned to sense flux generated by sensed electric current flowing through one or more additional electrical conductors. The electrical system may also include a control circuit operable to receive the output signal of the first magnetoresistive sensor and adjust the control current that generates the first control flux in a manner to cause the output signal from the first magnetoresistive sensor to substantially coincide with a predetermined target.