Physical quantity sensor

Patent metadata

Field	Value
Publication number	US-9310203-B2
Application number	US-201113638226-A
Country	US
Kind code	B2
Filing date	Mar 30, 2011
Priority date	Mar 31, 2010
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

An object of the invention is to provide a physical quantity sensor capable of producing a highly accurate physical quantity detection signal. The physical quantity sensor has an oscillator for converting an externally applied physical quantity into an electrical signal, an oscillation circuit which makes the oscillator oscillate, and a detector circuit for detecting a to-be-detected signal output from the oscillator by using a detection signal output from the oscillation circuit, includes a delta-sigma modulator, preceding the detector circuit, for delta-sigma modulating either one of the detection signal output from the oscillation circuit and the to-be-detected signal output from the oscillator, and for outputting a modulated signal, a variable voltage source capable of varying an output voltage, and a control unit for controlling the output voltage of the variable voltage source, and wherein the delta-sigma modulator performs the delta-sigma modulation by using a feedback signal created based on the output voltage.

First claim

What is claimed is:

1. A physical quantity sensor comprising:
an oscillator for converting an externally applied physical quantity into an electrical signal;
an oscillation circuit for causing said oscillator to oscillate, and for outputting a detection signal and a to-be-detected signal from said oscillator;
a delta-sigma modulator for delta-sigma modulating either one of said detection signal and said to-be-detected signal, and for outputting a modulated signal;
a detector circuit for detecting the other one of said detection signal and said to-be-detected signal by using said modulated signal, and for outputting a outputted signal;
a variable voltage source capable of varying an output voltage in accordance with the individual differences of said oscillator; and
a control unit for controlling said output voltage of said variable voltage source,
wherein said delta-sigma modulator performs said delta-sigma modulation by using a feedback signal created based on said output voltage.

2. The physical quantity sensor according to claim 1 , further comprising a memory for storing data in accordance with said oscillator,
wherein said control unit controls the output voltage of said variable voltage source, based on said data.

3. The physical quantity sensor according to claim 1 , further comprising a temperature sensor for detecting an ambient temperature of said oscillator,
wherein said control unit controls the output voltage of said variable voltage source, based on an output of said temperature sensor.

4. The physical quantity sensor according to claim 1 , further comprising:
a memory for storing data in accordance with said oscillator; and
a temperature sensor for detecting an ambient temperature of said oscillator,
wherein said control unit controls the output voltage of said variable voltage source, based on said data and on an output of said temperature sensor.

5. The physical quantity sensor according to claim 1 , further comprising a low-pass filter for removing an AC component from said output signal of said detector circuit.

6. The physical quantity sensor according to claim 5 , further comprising a second switching circuit for outputting, based on said modulated signal supplied from said delta-sigma modulator, either one of the output voltage of said variable voltage source and an inverted version of the output voltage of said variable voltage source,
wherein the signal output from said second switching circuit is used as said feedback signal.

7. The physical quantity sensor according to claim 1 , wherein said detector circuit further includes a first switching circuit for outputting, based on said modulated signal, the other one of said detection signal and said to-be-detected signal, or an inverted version of the other one of said detection signal and said to-be-detected signal.

Assignees

• Takase Yasuhide
• Citizen Holdings Co Ltd

Inventors

• Takase Yasuhide

Classifications

• G01C19/56 Primary

  Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces · CPC title

• G01P15/14

  by making use of gyroscopes (gyroscopes per se G01C19/00) · CPC title

• G01C19/5776 Primary

  Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719 · CPC title