System and method for automatic calibration of a transducer
First Claim
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1. An interface circuit comprising:
- a variable voltage bias generator configured to be coupled to a transducer;
a measurement circuit configured to be coupled to an output of the transducer, the measurement circuit configured to measure an output amplitude of the transducer; and
a calibration controller coupled to the bias generator and the measurement circuit, wherein the calibration controller is configured to set a sensitivity of the transducer and interface circuit during an auto-calibration sequence.
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Abstract
In accordance with an embodiment, an interface circuit includes a variable voltage bias generator coupled to a transducer, and a measurement circuit coupled to an output of the transducer. The measurement circuit is configured to measure an output amplitude of the transducer. The interface circuit further includes a calibration controller coupled to the bias generator and the measurement circuit, and is configured to set a sensitivity of the transducer and interface circuit during an auto-calibration sequence.
44 Citations
27 Claims
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1. An interface circuit comprising:
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a variable voltage bias generator configured to be coupled to a transducer; a measurement circuit configured to be coupled to an output of the transducer, the measurement circuit configured to measure an output amplitude of the transducer; and a calibration controller coupled to the bias generator and the measurement circuit, wherein the calibration controller is configured to set a sensitivity of the transducer and interface circuit during an auto-calibration sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of calibrating a transducer comprising:
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supplying a reference input signal for calibration to the transducer; and
performing an auto-calibration procedure, comprising;detecting a calibration procedure start condition; determining a fixed bias voltage; and
supplying the fixed bias voltage to the transducer;and the method further comprising; determining a sensitivity of the transducer a first time; and adjusting an amplifier gain if the sensitivity is not within a target sensitivity range. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A transducer system comprising:
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a microelectromechanical system (MEMS) microphone having a backplate with a first terminal and a membrane with a second terminal; and an auto-calibrating interface circuit comprising; an analog to digital converter (ADC); a bias generator coupled to the second terminal; and a calibration state machine coupled to the bias generator and configured to perform an auto-calibration procedure, comprising; determining a pull-in voltage of the MEMS microphone, and setting the bias generator based on the determined pull-in voltage; wherein the ADC, the bias generator, and the calibration state machine are deposed on a same integrated circuit. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification