Angular velocity detection circuit, angular velocity detection apparatus, and failure determination system

• US 8,677,822 B2
• Filed: 11/08/2012
• Issued: 03/25/2014
• Est. Priority Date: 07/17/2008
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Sato, Kenji
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US13/672,214
• Publication Number:
  US 20130061680A1
• Time in Patent Office: 502 Days
• Field of Search: 734/97, 735/041.2, 735/041.4, 735/041.6, 735/040.4, 73/13.7, 73/13.8, 73/17.7, 73/17.8
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5607 using vibrating tuning forks double-ended tuning forks using planar vibrating masses suspended at opposite ends G01C19/5719

Abstract

An angular velocity detection circuit is connected to a resonator for making excited vibration on the basis of a drive signal and detects an angular velocity. The angular velocity detection circuit includes: a self-vibration component extraction unit that receives, from the resonator, a detection signal including an angular velocity component based on a Coriolis force and a self-vibration component based on the excited vibration and extracts the self-vibration component from the detection signal; a direct-current conversion unit including an integration unit that integrates an output signal of the self-vibration component extraction unit; and a temperature characteristic compensation unit that compensates for a variation due to a temperature in an output signal of the direct-current conversion unit.

Claims

1. A circuit for use in a physical quantity detection device, comprising:

a self-vibration component extraction unit that receives, from a resonator, a signal that includes (i) a first component according to a magnitude of a physical quantity, and (ii) a second component based on an excited vibration, the self-vibration component extraction unit extracting the second component from the signal; and

a temperature characteristic compensation unit that compensates for variations due to a temperature in an output signal of the self-vibration component extraction unit.

2. The circuit for use in a physical quantity detection device according to claim 1, the resonator comprising:

a coupling arm that extends from a detection base portion;

a driving resonator element that extends from a driving base portion, the driving base portion arranged on the coupling arm and in a direction that intersects the direction in which the coupling arm extends; and

a detection resonator element that extends from the detection base portion in a direction that intersects the direction in which the coupling arm extends.

3. The circuit for use in a physical quantity detection device according to claim 1, wherein

the temperature characteristic compensation unit compensates for variations due to the temperature in the output signal of the self-vibration component extraction unit on the basis of a first-order term of a temperature characteristic in the output signal of the self-vibration component extraction unit.

4. The circuit for use in a physical quantity detection device according to claim 3, further comprising:

a storage unit that stores the first-order term of the temperature characteristic, wherein

the temperature characteristic compensation unit compensates for variations due to the temperature in the output signal of the self-vibration component extraction unit based on the first-order term of the temperature characteristic stored in the storage unit.

5. The circuit for use in a physical quantity detection device according to claim 1, further comprising:

a determination unit that monitors and determines the output signal of the temperature characteristic compensation unit.

6. The circuit for use in a physical quantity detection device according to claim 1, further comprising:

an amplification unit that amplifies the signal, the amplification unit provided before or after the self-vibration component extraction unit.

7. The circuit for use in a physical quantity detection device according to claim 1, further comprising:

an offset addition unit that adds an offset value to the signal, the offset addition unit provided before or after the temperature characteristic compensation unit.

8. A physical quantity detection device, comprising:

a resonator that generates a signal having (i) a first component according to a magnitude of a physical quantity, and (ii) a second component based on an excited signal;

a self-vibration component extraction unit that receives the signal and extracts the second component from the signal; and

a temperature characteristic compensation unit that compensates for variations due to a temperature in an output signal of the self-vibration component extraction unit.

9. The physical quantity detection device according to claim 8, the resonator comprising:

a coupling arm extending from a detection base portion;

a driving resonator element that extends from a driving base portion, the driving base portion arranged on the coupling arm and in a direction that intersects the direction in which the coupling arm extends; and

a detection resonator element that extends from the detection base portion in a direction that intersects the direction in which the coupling arm extends.

10. The circuit for use in a physical quantity detection device according to claim 8, wherein

the temperature characteristic compensation unit compensates for a variation due to the temperature in the output signal of the self-vibration component extraction unit on the basis of a first-order term of a temperature characteristic in the output signal of the self-vibration component extraction unit.

11. The physical quantity detection device according to claim 10, further comprising:

a storage unit that stores the first-order term of the temperature characteristic, wherein

the temperature characteristic compensation unit compensates for variations due to the temperature in the output signal of the self-vibration component extraction unit based on the first-order term of the temperature characteristic stored in the storage unit.

12. The physical quantity detection device according to claim 8, further comprising:

a determination unit that monitors and determines the output signal of the temperature characteristic compensation unit.

13. The physical quantity detection device according to claim 8, further comprising:

an amplification unit that amplifies the signal, the amplification unit provided before or after the self-vibration component extraction unit.

14. The physical quantity detection device according to claim 8, further comprising:

an offset addition unit that adds an offset value to the signal, the offset addition unit provided before or after the temperature characteristic compensation unit.

15. A failure determination system, comprising:

the physical quantity detection device according to claim 8, and

an external failure determination unit that (i) receives an output signal from the temperature characteristic compensation unit, and (ii) determines whether there is a failure in the physical quantity detection device.