Apparatus and method for multi-axis capacitive sensing

A method for measuring change in capacitance of a plurality of differential capacitors, wherein common electrodes of each differential capacitor are coupled, the method comprising the steps of, for each of the plurality of differential capacitors:

• applying a first input voltage to a first non-common electrode of a selected differential capacitor, a second input voltage to a second non-common electrode of the selected differential capacitor, and a third input voltage to a first non-common electrode and a second non-common electrode of each of the differential capacitors except the selected differential capacitor;
• latching a first output voltage of the common electrodes onto one of a plurality of demodulators;
• applying the first input voltage to the second non-common electrode of the selected differential capacitor, the second input voltage to the first non-common electrode of the selected differential capacitor, and the third input voltage to the first non-common electrode and the second non-common electrode of each of the differential capacitors except the selected differential capacitor;
• applying a second output voltage of the common electrodes tot he demodulator;
• and
• determining the change in capacitance of the selected differential capacitor from the first output voltage;
• wherein a different demodulator is activated for each of the plurality of differential capacitors.

A method of sensing capacitance, comprising:

• providing a movable mass having a first and a second electrode, a first set of fixed electrodes arranged relative to the first movable mass electrode to form a first differential capacitor, and a second set of fixed electrodes arranged relative to the second movable mass electrode to form a second differential capacitor;
• wherein the first and second differential capacitors are arranged relative to one another to respond to different force components;
• and
• detecting a change in capacitance of the first differential capacitor during a first time period and a change in capacitance of the second differential capacitance during a second time period.

A method of sensing capacitance comprising:

• providing a first capacitive structure arranged to change capacitive values in response to a first force component;
• and a second capacitive structure arranged to change capacitive values in response to a second force component;
• charging the first capacitive structure
• detecting a capacitance value in a first time period;
• charging the second capacitive structure;
• and
• detecting a capacitance value in a second time period that does not overlap with the first period.