Angular velocity sensor and angular velocity sensor control method

Patent metadata

Field	Value
Publication number	US-11428705-B2
Application number	US-201816500412-A
Country	US
Kind code	B2
Filing date	Apr 9, 2018
Priority date	Apr 17, 2017
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

An angular velocity sensor includes an angular velocity sensor element, a drive circuit, a detection circuit, and a reference potential supply circuit. The angular velocity sensor element has a monitor electrode, a drive electrode, a sense electrode, and a weight. The reference potential supply circuit supplies a reference potential to the angular velocity sensor element. The reference potential supply circuit has a first CV converter, a second CV converter, a comparator, and a reference potential adjustment circuit. The first CV converter is connected to the monitor electrode. The second CV converter is connected to the sense electrode. The comparator compares a frequency of a signal being output from the first CV converter with a frequency of a signal being output from the second CV converter, and outputs a signal depending on a result of the comparison.

First claim

The invention claimed is:

1. An angular velocity sensor comprising:
an angular velocity sensor element including:
a monitor electrode;
a drive electrode;
a sense electrode; and
a weight;

a drive circuit that drives the weight by applying an electric signal to the drive electrode;
a detection circuit that receives an electric signal generated by displacement of the weight from the sense electrode; and
a reference potential supply circuit that supplies a reference potential to the angular velocity sensor element,
wherein the reference potential supply circuit includes:
a first capacitance-to-voltage (CV) converter connected to the monitor electrode;
a second CV converter connected to the sense electrode;
a comparator that compares a frequency of a signal being output from the first CV converter with a frequency of a signal being output from the second CV converter and outputs a signal depending on a result of the comparison; and
a reference potential adjustment circuit that receives the signal depending on the result of the comparison and outputs the signal to the first CV converter or the second CV converter.

2. The angular velocity sensor according to claim 1 , wherein
the first CV converter has a first amplifier and a second amplifier,
the second CV converter has a third amplifier and a fourth amplifier, and
a non-inverting input terminal of each of the first amplifier and a non-inverting input terminal of the second amplifier receives the signal from the reference potential adjustment circuit.

3. The angular velocity sensor according to claim 2 , wherein
the monitor electrode has a first monitor electrode and a second monitor electrode,
to an inverting input terminal of the first amplifier, a signal from the first monitor electrode is input, and
to an inverting input terminal of the second amplifier, a signal from the second monitor electrode is input.

4. The angular velocity sensor according to claim 2 , wherein
the sense electrode has a first sense electrode and a second sense electrode,
to an inverting input terminal of the third amplifier, a signal from the first sense electrode is input, and
to an inverting input terminal of the fourth amplifier, a signal from the second sense electrode is input.

5. The angular velocity sensor according to claim 2 , wherein
the reference potential adjustment circuit has a first variable gain amplifier and a second variable gain amplifier,
an output from the first variable gain amplifier is input to the non-inverting input terminal of the first amplifier and the non-inverting input terminal of the second amplifier, and
an output from the second variable gain amplifier is input to a non-inverting input terminal of the third amplifier and a non-inverting input terminal of the fourth amplifier.

6. An angular velocity sensor comprising:
an angular velocity sensor element having:
a monitor electrode;
a drive electrode;
a sense electrode; and
a weight; and

a circuit electrically connected to the monitor electrode, the drive electrode, and the sense electrode,
wherein the circuit has:
a first CV converter connected to the monitor electrode;
a second CV converter connected to the sense electrode;
a comparator that a signal from the first CV converter and a signal from the second CV converter are input to; and
an output circuit that a signal from the comparator is input to and that outputs a signal to the first CV converter or the second CV converter.

7. The angular velocity sensor according to claim 6 , wherein
the first CV converter has a first amplifier and a second amplifier,
the second CV converter has a third amplifier and a fourth amplifier, and
the first amplifier and the second amplifier are connected to the output circuit.

8. The angular velocity sensor according to claim 7 , wherein
the monitor electrode has a first monitor electrode and a second monitor electrode,
the first amplifier is connected to the first monitor electrode, and
the second amplifier is connected to the second monitor electrode.

9. The angular velocity sensor according to claim 7 , wherein
the sense electrode has a first sense electrode and a second sense electrode,
the third amplifier is connected to the first sense electrode, and
the fourth amplifier is connected to the second sense electrode.

10. The angular velocity sensor according to claim 7 , wherein
the output circuit has a first variable gain amplifier and a second variable gain amplifier,
the first variable gain amplifier is connected to the first amplifier and the second amplifier, and
the second variable gain amplifier is connected to the third amplifier and the fourth amplifier.

11. A method for controlling an angular velocity sensor including an angular velocity sensor element, the angular velocity sensor element including a monitor electrode, a drive electrode, a sense electrode, and a weight, the method comprising:
a first step of CV converting a signal from the monitor electrode;
a second step of CV converting a signal from the sense electrode;
a third step of comparing the signal having been CV converted in the first step with the signal having been CV converted in the second step; and
a fourth step of changing a signal to be supplied to the monitor electrode or the sense electrode, based on a result of the comparison obtained in the third step.

12. The method for controlling an angular velocity sensor according to claim 11 , wherein in the fourth step, the signal to be supplied to the monitor electrode and the signal to be supplied to the sense electrode are independently changed.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Suzuki Hirotsugu
• Tsukamoto Kazuma

Classifications

• G01C19/5726 Primary

  Signal processing · CPC title

• G01C19/5747

  each sensing mass being connected to a driving mass, e.g. driving frames · CPC title

• G01P3/4802 Primary

  by using electronic circuits in general · CPC title

• G01P3/4805

  by using circuits for the electrical integration of the generated pulses (measuring impulse frequency by integration G01R23/09) · CPC title

• G01P3/483

  delivered by variable capacitance detectors · CPC title