Physical-quantity detection circuit, physical-quantity sensor, and electronic device

Patent metadata

Field	Value
Publication number	US-10018468-B2
Application number	US-201414911253-A
Country	US
Kind code	B2
Filing date	Oct 23, 2014
Priority date	Nov 14, 2013
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A physical-quantity sensor is configured to be used with a physical-quantity sensor element that outputs a sensor signal in response to a physical quantity. A physical-quantity detection circuit of the physical-quantity sensor includes a signal generating unit for generating a detecting signal and a multiplier that multiplies the sensor signal by the detecting signal. The signal generating unit converts a first phase of a predetermined signal having a frequency corresponding to a frequency of the sensor signal, into a second phase, and calculates an amplitude value corresponding to the second phase as to generate the detecting signal. This physical-quantity sensor improves accuracy of phase adjustment without increasing a sampling frequency.

First claim

The invention claimed is:

1. A physical-quantity detection circuit to be used with a physical-quantity sensor element that outputs a sensor signal in response to a physical quantity, the physical-quantity detection circuit comprising:
a signal generating unit for generating a detecting signal;
an analog-digital conversion circuit for converting the sensor signal into a digital sensor signal;
a multiplier for multiplying the digital sensor signal by the detecting signal, and
an unnecessary-signal cancelling section provided between the analog-digital conversion circuit and the multiplier;
wherein the signal generating unit is configured to:
generate a predetermined signal having a frequency corresponding to a frequency of the sensor signal;
generate a cancelling signal based on the predetermined signal; and
generate the detecting signal based on the predetermined signal,

wherein the digital sensor signal contains an unnecessary signal, and
wherein the unnecessary-signal cancelling section adds the cancelling signal to the digital sensor signal for reducing the unnecessary signal.

2. The physical-quantity detection circuit according to claim 1 ,
wherein the physical-quantity sensor element outputs the sensor signal in response to the physical quantity while vibrating, and
wherein the predetermined signal is an oscillating signal according to a vibration of the sensor element.

3. The physical-quantity detection circuit according to claim 1 ,
wherein the signal generating unit converts a first phase of the predetermined signal into a second phase by calculation.

4. The physical-quantity detection circuit according to claim 1 ,
wherein the signal generating unit includes a correction-amount generator and a sinewave generating unit,
wherein the correction-amount generator includes a temperature sensor that obtains temperature data, and a memory section that stores a correction amount corresponding to the temperature data, and
wherein the sinewave generating unit converts a first phase of the predetermined signal into a second phase based on the correction amount.

5. The physical-quantity detection circuit according to claim 1 , wherein the physical quantity is an angular velocity.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Murakami Hideyuki
• Kawai Takashi

Classifications

• G01C19/5776 Primary

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

• G01C19/5614 Primary

  Signal processing · CPC title

• G01P15/097

  by vibratory elements · CPC title