Conditioner circuit for magnetic field sensor

摘要

A circuit for sensing a magnetic field has at least one saturable coil (L1). The circuit includes switches (S1, S2) controlled by a comparator (12) to drive the coil (L1) to saturation by alternating polarities of current. In the absence of an external magnetic field the currents are balanced. An applied external magnetic field causes an unbalance in the coil (L1) in reaching saturation. An unbalance current is applied through a sensing resistor (R2) to an integrator (20) to develop an output voltage (Vo) as a measure of the applied magnetic field. The switches (S1, S2) are implemented by transistor switches. Dual (FIG. 1) and single (FIG. 2) supply rail circuits are disclosed. The circuit finds particular application in torque transducers using magnetoelastic elements.