Patent ID: 11933642
Assignee: HITACHI ASTEMO, LTD.
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G  H

Claim 0:
1. A two-wire displacement sensor device comprising:
an LC oscillation circuit including a coil whose inductance changes in accordance with a displacement amount of an object and an oscillation unit provided with a capacitor and an amplifying element; and
an interface unit serving as a signal output unit and a power supply input unit,
wherein the interface unit includes a constant current circuit that outputs at least two current values,
wherein the constant current circuit includes
a first constant current circuit that is connected between a first wire and a second wire and is configured to output an alternating current signal having a current waveform to the first wire when the first constant current circuit is switched between an ON state and an OFF state based on an alternating current signal having a voltage waveform obtained from the LC oscillation circuit,
a second constant current circuit that is connected between the first wire and the second wire and is constantly turned on, and
a smoothing capacitor that is connected between the second wire and a reference potential line and is configured to generate a power supply voltage of the oscillation unit, and

wherein the first wire serves as a current signal output line that outputs the alternating current signal having the current waveform and a direct current power supply voltage input line to which a direct current power supply voltage is input.