Sensor device

• US 5,822,369 A
• Filed: 08/28/1995
• Issued: 10/13/1998
• Est. Priority Date: 09/13/1994
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Araki, Toru
• Primary Examiner(s): VO, DON NGUYEN
• Application Number:
  US08/520,364
• Time in Patent Office: 1,142 Days
• Field of Search: 375/237, 327/51, 327/73, 364/555, 364/557, 340/870.17, 340/870.21, 340/870.23
• US Class Current: 375/237
• CPC Class Codes: G01D 5/243 influencing the phase or frequency of ac
• CPC Class Codes: H03M 1/60 with intermediate conversion to frequency of pulses

Abstract

A sensor device includes a voltage-to-pulse-number converter having a timing controller. When power is supplied to the converter from a power circuit through a power line, a timer circuit inhibits itself from performing a control operation until operations of a sensor and an amplifier become stable. After a predetermined period of time has passed, the inhibition of the controls is canceled. Then, an analog-to-digital (A-D) conversion of an output of the amplifier by the A-D converter is performed. Subsequently, a counter counts down from a value obtained from the A-D conversion. When the output of the counter becomes 0, the operation of the counter is stopped. Clock signals used for the operation of the counter are input to the pulse output circuit which is enabled only when the counter operates. Thereby, the timing controller outputs to an event counter a pulse signal having a number of pulses proportional to an output of the sensor. The sensor device obtains high precision data. Further, the power consumption of the sensor device is reduced. Consequently, the load imposed on a microcomputer is lightened.

Claims

1. A sensor device comprising:

sensor means for detecting a physical Quantity and for outputting a detection voltage corresponding to the physical quantity;

amplification means for amplifying the detection voltage and producing an amplified detection voltage; and

voltage-to-pulse-number conversion means for outputting a pulsed signal having a number of pulses proportional to the amplified detection voltage according to a data transmission requesting signal supplied from an external source, wherein the data transmission requesting signal is a power turn-on signal supplied from the external source, and the voltage-to-pulse-number conversion means comprises;

a clock generator;

a timing controller;

an analog-to-digital converters a counter; and

a pulse output circuit, wherein;

the clock generator generates a clock signal having a predetermined frequency, according to the power turn-on signal,

the timing controller causes the analog-to-digital converter to perform an analog-to-digital conversion of the amplified detection voltage,

the timing controller causes the counter to count down from a value obtained as the result of the analog-to-digital conversion to 0, and

the timing controller causes the pulse output circuit to output the clock signal generated by the clock generator as the pulsed signal only when the counter operates.

2. The sensor device as set forth in claim 1, wherein the voltage-to-pulse-number conversion means comprises a timer circuit for outputting a timer signal having a first duration according to the power turn-on signal, wherein the timing controller inhibits itself from performing a control operation for the first duration, until operations of the sensor means and the amplification means become stable.

3. A sensor device comprising:

sensor means for detecting a physical quantity and for outputting a detection voltage corresponding to the physical quantity;

amplification means for amplifying the detection voltage and producing an amplified detection voltage; and

voltage-to-pulse-number conversion means for outputting a pulsed signal having a number of pulses proportional to the amplified detection voltage according to a data transmission requesting signal supplied from an external source, wherein the data transmission requesting signal is a power turn-on signal supplied from the external source, and the voltage-to-pulse-number conversion means includes;

a clock generator;

a timing controller;

a counter;

a digital-to-analog converter;

a comparator; and

a pulse output circuit, wherein;

the clock generator generates a clock signal having a first frequency, according to the power turn-on signal,

the timing controller causes the counter to count up from 0,

the timing controller causes the digital-to-analog converter to perform a digital-to-analog conversion of a count obtained by the counter,

the timing controller causes the comparator to compare an output of the digital-to-analog converter with the amplified detection voltage, and

the timing controller causes the pulse output circuit to output the clock signal generated by and sent from the clock generator as the pulsed signal only until the output of the digital-to-analog converter equals the amplified detection voltage.

4. The sensor device as set forth in claim 3, wherein the voltage-to-pulse-number conversion means comprises a timer circuit for outputting a timer signal having a first duration according to the power turn-on signal, wherein the timing controller inhibits itself from performing a control operation for the first duration, until operations of the sensor means and the amplification means become stable.

5. A sensor device comprising:

sensor means for detecting a physical quantity and for outputting a detection voltage corresponding to the physical quantity;

amplification means for amplifying the detection voltage and producing an amplified detection voltage; and

voltage-to-pulse-number conversion means for outputting a pulsed signal having a number of pulses proportional to the amplified detection voltage according to a data transmission requesting signal supplied from an external source, wherein the data transmission requesting signal is a data conversion instruction signal sent from the external source, and the voltage-to-pulse-number conversion means comprises;

a clock generator;

a timing controller;

an analog-to-digital converter;

a counter; and

a pulse output circuit, wherein;

the clock generator generates a clock signal having a first frequency, according to the data conversion instruction signal,

the timing controller causes the analog-to-digital converter to perform an analog-to-digital conversion of the amplified detection voltage,

the timing controller causes the counter to count down from a value obtained as the result of the analog-to-digital conversion to 0, and

the timing controller causes the pulse output circuit to output the clock signal generated by the clock generator as the pulsed signal only when the counter operates.

6. The sensor device as set forth in claim 5, wherein the voltage-to-pulse-number conversion means comprises a timer circuit for outputting a timer signal having a first duration according to the data conversion instruction signal, wherein the timing controller inhibits itself from performing a control operation for the first duration, until operations of the sensor means and the amplification means become stable.

7. A sensor device comprising:

sensor means for detecting a physical quantity and for outputting a detection voltage corresponding to the physical quantity;

amplification means for amplifying the detection voltage and producing an amplified detection voltage; and

voltage-to-pulse-number conversion means for outputting a pulsed signal having a number of pulses proportional to the amplified detection voltage according to a data transmission requesting signal supplied from an external source, wherein the data transmission requesting signal is a data conversion instruction signal sent from the external source, and the voltage-to-pulse-number conversion means comprises;

a clock generator;

a timing controller;

a counter;

a digital-to-analog converter;

a comparator; and

a pulse output circuit, wherein;

the clock generator generates a clock signal having a first frequency according to the data conversion instruction signal,

the timing controller causes the counter to count up from 0,

the timing controller causes the digital-to-analog converter to perform a digital-to-analog conversion of a count produced by the counter,

the timing controller causes the comparator to compare the output of the digital-to-analog converter with the amplified detection voltage, and

the timing controller causes the pulse output circuit to output the clock signal generated by the clock generator as the pulsed signal only until the output of the digital-to-analog converter becomes equal to the amplified detection voltage.

8. The sensor device as set forth in claim 7, wherein the voltage-to-pulse-number conversion means comprises a timer circuit for outputting a timer signal having a first duration according to the data conversion instruction signal, wherein the timing controller inhibits itself from performing a control operation for the first duration, until operations of the sensor means and the amplification means become stable.