MEMS SENSOR WITH COMPENSATION OF RESIDUAL VOLTAGE
First Claim
1. A method for compensating for a residual voltage on an accelerometer, comprising:
- applying, to a plurality of auxiliary electrodes located opposite one or more planar surfaces of one or more proof masses, an auxiliary signal having a first harmonic frequency;
determining, based on a signal from one or more sense electrodes located opposite the one or more planar surfaces, a sensed signal;
identifying, from the sensed signal, a portion of the sensed signal having the first harmonic frequency;
determining, based on the portion of the sensed signal, that the residual voltage is present on the one or more proof masses or on the one or more sense electrodes; and
modifying the operation of the accelerometer based on the determination that the residual voltage is present on the one or more proof masses or on the electrodes.
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Accused Products
Abstract
A microelectromechanical (MEMS) sensor, such as an accelerometer, has one more proof masses that respond to movement of the sensor, the movement of which is measured based on a distance between the one or more proof masses and on one or more sense electrodes. The accelerometer also has a plurality of auxiliary electrodes and a signal generator configured to apply an auxiliary signal having a first harmonic frequency to the plurality of auxiliary electrodes. Circuitry receives a sensed signal from the plurality of sense electrodes and identifies a portion of the sensed signal having the first harmonic frequency. Based on this identified portion of the sensed signal, the circuitry determines whether a residual voltage is present on the one or more proof masses or on the one or more sense electrodes, and the circuitry modifies the operation of the accelerometer when the residual voltage is determined to be present in order to compensate for the residual voltage.
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Citations
20 Claims
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1. A method for compensating for a residual voltage on an accelerometer, comprising:
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applying, to a plurality of auxiliary electrodes located opposite one or more planar surfaces of one or more proof masses, an auxiliary signal having a first harmonic frequency; determining, based on a signal from one or more sense electrodes located opposite the one or more planar surfaces, a sensed signal; identifying, from the sensed signal, a portion of the sensed signal having the first harmonic frequency; determining, based on the portion of the sensed signal, that the residual voltage is present on the one or more proof masses or on the one or more sense electrodes; and modifying the operation of the accelerometer based on the determination that the residual voltage is present on the one or more proof masses or on the electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An accelerometer, comprising:
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one or more proof masses having one or more planar surfaces; a plurality of auxiliary electrodes located opposite the one or more planar surfaces; a signal generator configured to apply an auxiliary signal to the plurality of auxiliary electrodes, the auxiliary signal having a first harmonic frequency; a plurality of sense electrodes located opposite the one or more planar surfaces; and circuitry coupled to provide a sensed signal based on a signal from the plurality of sense electrodes, wherein the circuitry identifies a portion of the sensed signal having the first harmonic frequency and determines, based on the portion of the sensed signal, that a residual voltage is present on the one or more proof masses or the plurality of sense electrodes, and wherein the circuitry modifies the operation of the accelerometer based on a determination that the residual voltage is present on the one or more proof masses or the plurality of sense electrodes.
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18. An accelerometer, comprising:
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one or more proof masses having one or more planar surfaces; a plurality of auxiliary electrodes located opposite the one or more planar surfaces; a plurality of sense electrodes located opposite the one or more planar surfaces and configured to output a signal representative of a capacitance; a first signal generator configured to apply an auxiliary signal to the plurality of auxiliary electrodes, the auxiliary signal having a first harmonic frequency; a second signal generator configured to apply an operating signal to the accelerometer, the operating signal having an operating frequency different than the first harmonic frequency; and circuitry configured to determine a sensed signal from signal representative of the capacitance, the circuitry configured to identify a first portion of the sensed signal having the first harmonic frequency and to determine, based on the first portion of the sensed signal, that a residual voltage is present on the one or more proof masses or on the plurality of sense electrodes, wherein the circuitry is further configured to compensate for the residual voltage in response to a determination that the residual voltage is present on the one or more proof masses or on the plurality of sense electrodes, and wherein the circuitry is further configured to identify a second portion of the sensed signal having the operating frequency and to determine, based on the second portion of the sensed signal, a linear acceleration for the accelerometer. - View Dependent Claims (19, 20)
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Specification