Noise reduction method with chopping for a merged MEMS accelerometer sensor
First Claim
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1. An apparatus comprising:
- a capacitance-to-voltage converter circuit configured to be electrically coupled to a micro-electromechanical system (MEMS) sensor circuit, the capacitance-to-voltage converter circuit including;
a differential chopping circuit path configured to receive a differential MEMS sensor output signal and invert a polarity of the differential chopping circuit path; and
a differential sigma-delta analog to digital converter (ADC) circuit configured to sample the differential MEMS sensor output signal and provide a digital signal representative of a change in capacitance of the MEMS sensor.
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Abstract
An apparatus includes a capacitance-to-voltage converter circuit configured to be electrically coupled to a micro-electromechanical system (MEMS) sensor circuit. The capacitance-to-voltage converter circuit includes a differential chopping circuit path configured to receive a differential MEMS sensor output signal and invert a polarity of the differential chopping circuit path, and a differential sigma-delta analog to digital converter (ADC) circuit configured to sample the differential MEMS sensor output signal and provide a digital signal representative of a change in capacitance of the MEMS sensor.
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Citations
22 Claims
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1. An apparatus comprising:
a capacitance-to-voltage converter circuit configured to be electrically coupled to a micro-electromechanical system (MEMS) sensor circuit, the capacitance-to-voltage converter circuit including; a differential chopping circuit path configured to receive a differential MEMS sensor output signal and invert a polarity of the differential chopping circuit path; and a differential sigma-delta analog to digital converter (ADC) circuit configured to sample the differential MEMS sensor output signal and provide a digital signal representative of a change in capacitance of the MEMS sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus comprising:
a capacitance-to-voltage converter circuit configured to be electrically coupled to a MEMS sensor circuit, the capacitance-to-voltage converter circuit including; a differential circuit path configured to receive a differential MEMS sensor output signal; a differential sigma-delta ADC circuit configured to sample the differential MEMS sensor output signal and provide a digital signal representative of a change in capacitance of the MEMS sensor, wherein the differential sigma-delta ADC circuit includes a comparator circuit; and a pseudo-random noise generator circuit electrically coupled to the comparator circuit and configured to apply dither noise to an input of the comparator circuit. - View Dependent Claims (11, 12, 13)
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14. A method comprising:
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sensing an output of a micro-electromechanical system (MEMS) sensor to create a differential sensor output signal; applying the output of the MEMS sensor to a differential chopping circuit path, wherein a polarity of the differential chopping circuit path is inverted at timed intervals; and sampling the chopped MEMS sensor output signal with a differential sigma-delta analog to digital converter (ADC) circuit to generate a digital signal representative of a change in capacitance of the MEMS sensor. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification