CONTROLLER FOR MAGNETOELECTRIC CONVERSION SENSOR

摘要

PURPOSE:To enable the detecting of fine changes in the magnetic flux density by providing a power source from which a voltage is supplied to a magnetoelectric conversion sensor varying cyclically in a range of a specified value while being increasing gradually. CONSTITUTION:A power source section 78 converts a power source of a fixed voltage to a saw-tooth shaped oscillation waveform with an oscillation circuit. As a result, the voltage of a supply power source at a point B varies cyclically in a specified range of about 3.36-4V while increasing gradually at each cycle. The power source of this oscillation waveform is applied to Hall ICs71A and 71B. When a magnetic flux density working on the Hall ICs 71A and 71B lowers to ranges of a working magnetic flux density and a return magnetic flux density (range of hysteresis width) from the working magnetic flux density, the output voltages of the Hall ICs 71A and 71B goes to a high level. This enables the reducing of the hysteresis width of the output characteristics of electric signals (ON signal and OFF signal)with respect to the magnetic flux density of the Hall ICs71A and 71B thereby allowing the detection of fine changes in the magnetic flux density eventually.