Thermal convection accelerometer with closed-loop heater control
First Claim
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1. An integrated convective accelerometer chip, comprising:
- a convective acceleration sensor including a heater element and a plurality of temperature sensing elements, the plurality of temperature sensing elements being operative to generate a differential output voltage indicative of a magnitude of acceleration applied along at least one axis passing through the heater element and the plurality of temperature sensing elements;
amplification circuitry configured to receive the differential output voltage generated by the plurality of temperature sensing elements and operative to generate a corresponding common-mode output voltage, wherein the common-mode output voltage generated by the amplification circuitry is representative of a common-mode voltage across the plurality of temperature sensing elements; and
control circuitry configured to receive the common-mode output voltage generated by the amplification circuitry and operative to generate a control output proportional thereto, the control circuitry being further operative to regulate the common-mode voltage across the temperature sensing elements using the control output.
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Abstract
An integrated convective accelerometer device. The device includes a thermal acceleration sensor having a thermopile and a heater element; control circuitry for providing closed-loop control of the thermopile common-mode voltage; an instrumentation amplifier; clock generation circuitry; voltage reference circuitry; a temperature sensor; and, output amplifiers. The device can be operated in an absolute or ratiometric mode. Further, the device is formed in a silicon substrate using standard semiconductor processes and is packaged in a standard integrated circuit package.
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Citations
25 Claims
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1. An integrated convective accelerometer chip, comprising:
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a convective acceleration sensor including a heater element and a plurality of temperature sensing elements, the plurality of temperature sensing elements being operative to generate a differential output voltage indicative of a magnitude of acceleration applied along at least one axis passing through the heater element and the plurality of temperature sensing elements;
amplification circuitry configured to receive the differential output voltage generated by the plurality of temperature sensing elements and operative to generate a corresponding common-mode output voltage, wherein the common-mode output voltage generated by the amplification circuitry is representative of a common-mode voltage across the plurality of temperature sensing elements; and
control circuitry configured to receive the common-mode output voltage generated by the amplification circuitry and operative to generate a control output proportional thereto, the control circuitry being further operative to regulate the common-mode voltage across the temperature sensing elements using the control output. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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2. An integrated convective accelerometer chip, comprising:
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a convective acceleration sensor including a heater element and a plurality of temperature sensing elements, the plurality of temperature sensing elements being operative to generate a differential output voltage indicative of a magnitude of acceleration applied along at least one axis passing through the heater element and the plurality of temperature sensing elements;
amplification circuitry configured to receive the differential output voltage generated by the plurality of temperature sensing elements and operative to generate a corresponding common-mode output voltage; and
control circuitry configured to receive the common-mode output voltage generated by the amplification circuitry and operative to generate a control output proportional thereto, the control circuitry being further operative to regulate the common-mode output voltage using the control output, wherein the control circuitry is operative to regulate the common-mode voltage across the temperature sensing elements by regulating a current through the heater element. - View Dependent Claims (3, 4, 5, 6, 7)
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15. A method of operating a convective acceleration sensor, the convective acceleration sensor including a heater element and a plurality of temperature sensing elements, the method comprising the steps of:
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generating a differential output voltage by the plurality of temperature sensing elements, the differential output voltage being indicative of a magnitude of acceleration applied along at least one axis passing through the heater element and the plurality of temperature sensing elements;
generating a common-mode output voltage corresponding to the differential output voltage, the common-mode output voltage being representative of a common-mode voltage across the plurality of temperature sensing elements;
generating a control output proportional to the common-mode output voltage; and
regulating the common-mode voltage across the temperature sensing elements using the control output. - View Dependent Claims (20, 21, 23, 24, 25)
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16. A method of operating an integrated convective accelerometer chip, the chip including a convective acceleration sensor having a heater element and a plurality of temperature sensing elements, the method comprising the steps of:
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generating a differential output voltage indicative of a magnitude of acceleration applied along at least one axis passing through the heater element and the plurality of temperature sensing elements;
generating a common-mode output voltage corresponding to the differential output voltage;
generating a control output proportional to the common-mode output voltage; and
regulating the common-mode output voltage using the control output, wherein the regulating step includes the substep of regulating a current through the heater element. - View Dependent Claims (17, 18, 19, 22)
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Specification