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.