IC for sensor with a switchable low pass filter, sensor device and electronic apparatus

• US 9,644,964 B2
• Filed: 11/11/2014
• Issued: 05/09/2017
• Est. Priority Date: 11/12/2013
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Maki, Katsuhiko, Nakajima, Katsuhito
• Primary Examiner(s): Patel, Harshad R
• Assistant Examiner(s): Shah, Samir M
• Application Number:
  US14/538,286
• Publication Number:
  US 20150128699A1
• Time in Patent Office: 910 Days
• CPC Class Codes: G01C 19/00 Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
• CPC Class Codes: G01C 19/5776 Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719

Abstract

A IC for sensor includes a detector which detects an angular velocity signal based on a signal from a sensor element, an AD converter which converts an analog signal from the detector into a digital signal, and a DC component detector which detects a DC component from the digital signal output from the AD converter within a predetermined period of time.

Claims

1. An IC for sensor comprising:

a detector which detects an angular velocity signal based on a signal from a sensor element;

an AD converter which converts an analog signal from the detector into a digital signal; and

a DC component detector which detects a DC component from the digital signal output from the AD converter within a predetermined period of time, wherein the DC component detector includes a DC low pass filter circuit that filters the digital signal in accordance with a low pass cutoff frequency, the low pass cutoff frequency of the DC low pass filter circuit is switchably set to one of a first frequency or a second frequency lower than the first frequency.

2. The IC for sensor according to claim 1, further comprising:

a corrector which corrects the digital signal based on the DC component.

3. The IC for sensor according to claim 2 further comprising:

a register that includes a flag indicating the completion of the operation of detecting the DC component by the DC component detector when the flag is set, wherein the corrector corrects the digital signal based on the DC component in response to the flag being set.

4. A sensor device comprising:

a sensor element; and

the IC for sensor according to claim 3.

5. A sensor device comprising:

a sensor element; and

the IC for sensor according to claim 2.

6. An electronic apparatus comprising:

a sensor element; and

the IC for sensor according to claim 2.

7. The IC for sensor according to claim 1,

wherein the DC component detector includes a gain corrector which corrects a gain for each switch of the cutoff frequency.

8. A sensor device comprising:

a sensor element; and

the IC for sensor according to claim 7.

9. An electronic apparatus comprising:

a sensor element; and

the IC for sensor according to claim 7.

10. The IC for sensor according to claim 1, further comprising:

a pre-digital corrector which corrects an offset of the digital signal based on a set value between the AD converter and the DC component detector.

11. A sensor device comprising:

a sensor element; and

the IC for sensor according to claim 10.

12. An electronic apparatus comprising:

a sensor element; and

the IC for sensor according to claim 10.

13. The IC for sensor according to claim 1,

wherein the detection operation in the DC component detector is started based on a signal input from outside the IC for sensor.

14. A sensor device comprising:

a sensor element; and

the IC for sensor according to claim 13.

15. An electronic apparatus comprising:

a sensor element; and

the IC for sensor according to claim 13.

16. A sensor device comprising:

a sensor element; and

the IC for sensor according to claim 1.

17. An electronic apparatus comprising:

a sensor element; and

the IC for sensor according to claim 1.

18. The IC for sensor according to claim 1, wherein

the DC component detector detects the DC component of the digital signal with the low pass cutoff frequency of the DC low pass filter set to the second frequency.