PROTECTING SYSTEM FOR HALL ELEMENT TYPE TORQUE SENSOR

摘要

PURPOSE:To make it possible to realize an adequate fail-safe function by cutting a Hall-element current at the time of abnormality or power-ON resetting. CONSTITUTION:Currents to be supplied to Hall elements 1 and 2 are fed back and controlled through a differential amplifier part 5 and a signal judging part 6 based on voltages V1 and V2 of amplifier parts 3 and 4. The outputs are taken out through output terminals T1 and T2. The output from the amplifier part 5 is supplied to the judging part 6 as a signal Vf for a driving current for the elements 1 and 2. The judging part 6 outputs the signal as Vf=Vf' at the normal time. The elements 1 and 2 are driven by the current values determined by the signal Vf'. The judging part 6 has a function for cutting a Hall element current depending on the output signal from a processing part 7. The processing part 7 is connected to an input terminal CT1 for an abnormal signal S1 and an input terminal CT2 for a power-ON reset signal S2. The function is utilized when the current flowing through the elements 1 and 2 is controlled with the circuit part which is surrounded with a broken line and contains the judging part 6 and the processing part 7. The Hall element current is cut at the time of abnormality or power-ON resetting, and a fail-safe function is performed.