Resonant phase sensing of resistive-inductive-capacitive sensors

Patent metadata

Field	Value
Publication number	US-10908200-B2
Application number	US-201916267079-A
Country	US
Kind code	B2
Filing date	Feb 4, 2019
Priority date	Mar 29, 2018
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor at a driving frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure phase information associated with the resistive-inductive-capacitive sensor and based on the phase information, determine a displacement of a mechanical member relative to the resistive-inductive-capacitive sensor, wherein the displacement of the mechanical member causes a change in an impedance of the resistive-inductive-capacitive sensor.

First claim

What is claimed is:

1. A system comprising:
a resistive-inductive-capacitive sensor;
a driver configured to drive the resistive-inductive-capacitive sensor with a driving signal at a driving frequency;
a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to:
measure phase information associated with the resistive-inductive-capacitive sensor, wherein the phase information is relative to a phase of the driving signal; and
based on the phase information, determine a displacement of a mechanical member relative to the resistive-inductive-capacitive sensor, wherein the displacement of the mechanical member causes a change in an impedance of the resistive-inductive-capacitive sensor.

2. The system of claim 1 , wherein the measurement circuit is further configured to determine an occurrence of a physical interaction associated with a human-machine interface associated with the mechanical member based on the phase information.

3. The system of claim 2 , wherein the physical interaction comprises one of pressing of a virtual interface by a user of the system and releasing of a virtual interface by a user of the system.

4. The system of claim 1 , wherein the measurement circuit comprises a coherent incident/quadrature detector and the measurement circuit is configured to measure the phase information using the coherent incident/quadrature detector.

5. The system of claim 4 , wherein the driving frequency is selected based on a resonant frequency of the resistive-inductive-capacitive sensor.

6. The system of claim 4 , further comprising a control loop to track changes in operating parameters of the system by modifying one or more of the driving frequency and a phase shift associated with the phase information.

7. The system of claim 6 , wherein the control loop comprises at least one of a feedforward control loop component and a feedback control loop component.

8. The system of claim 7 , wherein the measurement circuit is further configured to:
measure amplitude information associated with the resistive-inductive-capacitive sensor; and
based on the amplitude information and the phase information, determine the changes in the operating parameters.

9. The system of claim 4 , further comprising:
a first analog-to-digital converter coupled to an output of an incident channel of the coherent incident/quadrature detector; and
a second analog-to-digital converter coupled to an output of a quadrature channel of the coherent incident/quadrature detector;
such that the coherent incident/quadrature detector operates in an analog signal domain.

10. The system of claim 4 , further comprising:
a first analog-to-digital converter interfaced between the resistive-inductive-capacitive sensor and an incident channel of the coherent incident/quadrature detector; and
a second analog-to-digital converter interfaced between the resistive-inductive-capacitive sensor and a quadrature channel of the coherent incident/quadrature detector;
such that the coherent incident/quadrature detector operates in a digital signal domain.

11. The system of claim 1 , wherein:
the resistive-inductive-capacitive sensor comprises a resistive element, a capacitive element, and an inductive element; and
one element of the resistive element, the capacitive element, and the inductive element is in series with at least one other element of the resistive element, the capacitive element, and the inductive element.

12. The system of claim 1 , wherein:
the resistive-inductive-capacitive sensor comprises a resistive element, a capacitive element, and an inductive element; and
one element of the resistive element, the capacitive element, and the inductive element is in parallel with at least one other element of the resistive element, the capacitive element, and the inductive element.

13. The system of claim 1 , further comprising a second resistive-inductive-capacitive sensor, wherein the driver is configured to simultaneously drive the resistive-inductive-capacitive sensor and the second resistive-inductive-capacitive sensor at the driving frequency.

14. The system of claim 1 , further comprising:
a second resistive-inductive-capacitive sensor; and
a time-division multiplexing control subsystem configured to:
time-division multiplex drive the resistive-inductive-capacitive sensor and the second resistive-inductive-capacitive sensor by the driver; and
time-division multiplex measure by the measurement circuit the phase information associated with the resistive-inductive-capacitive sensor and measure the phase information associated with the second resistive-inductive-capacitive sensor.

15. The system of claim 14 , wherein:
when the resistive-inductive-capacitive sensor is selected by the time-division multiplexing control subsystem for being driven by the driver and measured by the measurement circuit, the second resistive-inductive-capacitive sensor is placed in a low-impedance state; and
when the second resistive-inductive-capacitive sensor is selected by the time-division multiplexing control subsystem for being driven by the driver and measured by the measurement circuit, the resistive-inductive-capacitive sensor is placed in the low-impedance state.

16. The system of claim 1 , wherein the measurement circuit is further configured to quantify a duration of the displacement to more than one detection threshold.

17. The system of claim 1 , wherein the measurement circuit is further configured to quantify a magnitude of the displacement to more than one detection threshold.

18. The system of claim 1 , wherein the measurement circuit is configured to be duty-cycled in operation such that:
for a first portion of a cycle of the measurement circuit, the measurement circuit is in a low power mode; and
for a second portion of the cycle of the measurement circuit, the measurement circuit is in a high power mode in which the measurement circuit consumes more power than in the low power mode, and wherein the measurement performs measurement of the phase information and determination of the displacement during the second portion.

19. The system of claim 1 , wherein the mechanical member comprises a metal plate.

20. A method comprising:
measuring phase information associated with a resistive-inductive-capacitive sensor driven with a driving signal by a driver at a driving frequency, wherein the phase information is relative to a phase of the driving signal; and
based on the phase information, determining a displacement of a mechanical member relative to the resistive-inductive-capacitive sensor, wherein the displacement of the mechanical member causes a change in an impedance of the resistive-inductive-capacitive sensor.

21. The method of claim 20 , wherein the measurement circuit is further configured to determine an occurrence of a physical interaction associated with a human-machine interface associated with the mechanical member based on the phase information.

22. The method of claim 21 , wherein the physical interaction comprises one of pressing of a virtual interface by a user of the system and releasing of a virtual interface by a user of the system.

23. The method of claim 20 , wherein the measurement circuit comprises a coherent incident/quadrature detector and the measurement circuit is configured to measure the phase information using the coherent incident/quadrature detector.

24. The method of claim 23 , w

Assignees

• Cirrus Logic Int Semiconductor Ltd
• Cirrus Logic Inc

Inventors

• You Zhong
• Maru Siddharth
• Das Tejasvi
• Lapointe Luke
• King Eric J
• Doy Anthony S
• Marjianovic Srdjan
• Kinney Drew
• Beardsworth Matthew
• Marchais Emmanuel

Classifications

• G01R31/2601

  Apparatus or methods therefor (G01R31/2607, G01R31/2642 take precedence) · CPC title

• G01R27/02

  Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only G01R25/00) · CPC title

• G01D5/2026

  constituting a short-circuiting element · CPC title

• G01D5/243 Primary

  influencing the phase or frequency of AC · CPC title

• G01D5/202

  by movable a non-ferromagnetic conductive element (G01D5/2033 takes precedence) · CPC title