Dynamic capacitance-to-volvage offset cancellation

A microelectromechanical system (MEMS) sensor, comprising:

• a MEMS structure including one or more MEMS components that move in response to force of interest, wherein the movement causes a change of a sense capacitance of the MEMS sensor;
• a capacitance-to-voltage (C2V) converter configured to receive a capacitance signal that corresponds to the sense capacitance;
• a sense path coupled to the MEMS structure and the C2V converter to provide the capacitance signal to the C2V converter;
• one or more variable capacitors coupled to the sense path;
• and
• processing circuitry coupled to an output of the C2V converter and the one or more variable capacitors, wherein the processing circuitry is configured to receive an output signal from the output of the C2V converter, identify an offset signal portion of the output signal, and generate a variable capacitor control signal to modify a capacitance of the one or more variable capacitors to remove the offset signal portion from the output, wherein the processing circuitry comprises an analog stage coupled to receive the output signal from the output of the C2V converter and a digital stage coupled to receive an analog stage output signal, wherein the digital stage generates the variable capacitor control signal based on the analog stage output signal, and wherein the analog stage comprises an integrator and an analog-to-digital converter (ADC), and wherein the integrator is electrically coupled between the output of the C2V converter and the ADC, and wherein the digital stage is coupled between an ADC output and the one or more variable capacitors.

A method for removing offset from an output of a MEMS capacitance-to-voltage (C2V) converter, comprising:

• receiving, at an input of the C2V converter, a capacitance signal that corresponds to a movement of a component of a microelectromechanical system (MEMS) structure due to a force of interest from a sense path coupled to the MEMS structure and the C2V converter;
• outputting, from the C2V converter, an output signal, wherein the output signal includes an offset signal portion of the output signal;
• generating, by processing circuitry, a variable capacitor control signal to remove the offset signal portion from the output signal;
• and
• providing, from the processing circuitry to one or more variable capacitors coupled to the sense path, the variable capacitor control signal, wherein the one or more variable capacitors are coupled to the C2V converter to modify the received capacitance signal,
• wherein the MEMS structure comprises a MEMS gyroscope and is configured to sense a respective angular velocity about each of a plurality of sense axes to generate a plurality of capacitance signals, further comprising a multiplexer located within the sense path, wherein the multiplexer selectively provides one of the capacitance signals to the C2V converter via the sense path, and wherein the one or more variable capacitors is coupled to the sense path between the multiplexer and the C2V converter.

A method for removing a sampled offset from a sensed signal of a microelectromechanical system (MEMS) gyroscope, comprising:

• receiving, at an input of a C2V converter, a capacitance signal that corresponds to a movement of a component of a MEMS structure;
• outputting, from the C2V converter, an output signal;
• integrating the output signal;
• digitizing the integrated output signal, wherein the integrated and digitized output signal corresponds to an offset portion of the output signal;
• generating, by digital processing circuitry, a variable capacitor control signal to remove the offset portion of the output signal;
• and
• providing, from the digital processing circuitry to one or more variable capacitors, the variable capacitor control signal, wherein the one or more variable capacitors are coupled to the C2V converter to modify the received capacitance signal,
• wherein the processing circuitry comprises an analog stage coupled to receive the output signal from the output of the C2V converter and a digital stage coupled to receive an analog stage output signal, wherein the digital stage generates the variable capacitor control signal based on the analog stage output signal, and wherein the analog stage comprises an integrator and an analog-to-digital converter (ADC), and wherein the integrator is electrically coupled between the output of the C2V converter and the ADC, and wherein the digital stage is coupled between an ADC output and the one or more variable capacitors.