Methods and systems for detecting a capacitance using sigma-delta measurement techniques

A program product comprising:

• a) a proximity sensor program configured to determine a capacitance value of a first capacitance by performing the steps of:
• applying a voltage to the first capacitance;
• allowing the first capacitance to share charge with a second capacitance;
• outputting a quantized value reflective of whether a voltage on the integrating capacitance is past a threshold;
• changing a charge on the integrating capacitance by an amount of charge responsive to the voltage on the second capacitance being past the threshold, wherein the amount of charge is determined at least in part as a function of the quantized value;
• repeating each of the applying step, the allowing step, the outputting, and the changing step at least once to generate at least one additional quantized value, such that the quantized value and the at least one additional quantized value form a plurality of quantized values;
• and
• determining the capacitance value using the plurality of quantized values;
• and
• b) computer readable media bearing the proximity sensor program.

A controller including a memory, the memory including executable instructions for determining a capacitance value of a first capacitance by performing the steps of:

• repeatedly applying a predetermined voltage to the first capacitance;
• repeatedly sharing charge between the first capacitance and a second capacitance to accumulate charge on the second capacitance;
• repeatedly measuring voltage on the second capacitance using an input of the controller and generating quantized values responsive to the repeated measurings;
• repeatedly changing charge on the second capacitance based on the quantized values;
• and
• determining the capacitance value of the first capacitance using the quantized values.