Interface for MEMS inertial sensors
First Claim
1. An integrated circuit for interfacing with a MEMS sensor, comprising:
- an electrostatic actuation controller configured to generate an actuation signal and an excitation signal and to receive a sense information signal; and
a sensing capacitance-to-voltage converter responsive to a signal from the MEMS sensor for producing a sense signal;
wherein the electrostatic actuation controller is configured to, during at least some signal transitions of the actuation signal, apply a control signal to the sensing capacitance-to-voltage converter to cause it to be reset, disabled or powered down.
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Accused Products
Abstract
In a high-performance interface circuit for micro-electromechanical (MEMS) inertial sensors, an excitation signal (used to detect capacitance variation) is used to control the value of an actuation signal bit stream to allow the dynamic range of both actuation and detection paths to be maximized and to prevent folding of high frequency components of the actuation bit stream due to mixing with the excitation signal. In another aspect, the effects of coupling between actuation signals and detection signals may be overcome by performing a disable/reset of at least one of and preferably both of the detection circuitry and the MEMS detection electrodes during actuation signal transitions. In a still further aspect, to get a demodulated signal to have a low DC component, fine phase adjustment may be achieved by configuring filters within the sense and drive paths to have slightly different center frequencies and hence slightly different delays.
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Citations
27 Claims
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1. An integrated circuit for interfacing with a MEMS sensor, comprising:
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an electrostatic actuation controller configured to generate an actuation signal and an excitation signal and to receive a sense information signal; and a sensing capacitance-to-voltage converter responsive to a signal from the MEMS sensor for producing a sense signal; wherein the electrostatic actuation controller is configured to, during at least some signal transitions of the actuation signal, apply a control signal to the sensing capacitance-to-voltage converter to cause it to be reset, disabled or powered down. - View Dependent Claims (2, 3, 4)
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5. A method of interfacing with a MEMS sensor comprising a suspended mass, the method comprising:
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responsive to a sense signal output by the MEMS sensor, sensing capacitance variations caused by motion of the mass; producing an actuation signal to be applied to the MEMS sensor for causing an influence to be exerted upon the mass, and an excitation signal to be applied to at least one sense capacitor of the MEMS sensor; and during at least some signal transitions of the actuation signal, resetting, disabling or powering down said sensing in response to a control signal. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An integrated circuit for interfacing with a MEMS sensor comprising a suspended mass, the integrated circuit comprising:
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sensing circuitry responsive to a sense signal output by the MEMS sensor for sensing capacitance variations caused by motion of the mass; control circuitry for applying to the MEMS sensor an actuation signal to cause an influence to be exerted upon the mass, and an excitation signal to be applied to at least one sense capacitor of the MEMS sensor; and circuitry for, during at least some signal transitions of the actuation signal, applying a control signal to the sensing circuitry to reset, disable or power down said sensing circuitry. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification