Inductive Sensor for Measurement Device

• US 20200132510A1
• Filed: 10/25/2019
• Published: 04/30/2020
• Est. Priority Date: 10/25/2018
• Status: Active Grant

• Current Assignee: Pepperl + Fuchs GmbH
• Original Assignee: Pepperl + Fuchs GmbH
• Inventors: Kuhn, Thomas
• Granted Patent: US 11,169,004 B2
• Time in Patent Office: Days
• CPC Class Codes: G01D 5/202 by movable a non-ferromagnetic conductive element G01D5/2033 takes precedence
• CPC Class Codes: H03K 17/9547 with variable amplitude
• CPC Class Codes: H03K 2217/96038 Inductive touch switches

Abstract

An inductive sensor, particularly for a proximity sensor, includes a resonance circuit including a sensing coil and an amplifier comprising a first gain stage and a second gain stage each coupled via respective adjusting elements with the resonance circuit to inject energy for maintaining an oscillation of the resonance circuit. The first gain stage provides a substantially linear amplification and the second gain stage provides a comparator characteristics.

Claims

1. An inductive sensor, particularly for a proximity sensor, comprising:

a resonance circuit including a sensing coil;

an amplifier comprising a first gain stage and a second gain stage each coupled via respective adjusting elements with the resonance circuit to inject energy for maintaining an oscillation of the resonance circuit,

wherein the first gain stage provides a substantially linear amplification and the second gain stage provides a comparator characteristics.

2. The inductive Inductive sensor according to claim 1, wherein the adjusting elements are formed with resistors.

3. The inductive Inductive sensor according to claim 2, wherein at least one of the adjusting elements includes an electronic switch.

4. The inductive Inductive sensor according to claim 3, wherein a calibration unit is configured to control the at least one of the electronic switches, particularly by means of a pulse width modulated signal, to set an effective resistance of the respective adjusting element.

5. The inductive Inductive sensor according to claim 1, wherein the resonance circuit has a capacitor forming a parallel resonance circuit with the sensing coil.

6. The inductive Inductive sensor according to claim 1, wherein adjustment elements are coupled with the same or different nodes of the resonance circuit.

7. The inductive Inductive sensor device, particularly a proximity sensor, comprising an inductive sensor according to claim 1, wherein a signal analyzer is configured to receive an amplified oscillation signal at the output of the first gain stage and to provide a sensor signal indicative of the amplitude of an oscillation signal of the resonance circuit.

8. The inductive Inductive sensor device, particularly a proximity sensor, comprising an inductive sensor according to claim 1, wherein a signal analyzer is configured to receive an oscillation signal at the output of the resonance circuit and to provide a sensor signal indicative of the amplitude of an oscillation signal of the resonance circuit.