Methods and systems for detecting a capacitance using sigma-delta measurement techniques
First Claim
1. A program product comprising:
- a) a proximity sensor program configured to determine a capacitance value of a measurable capacitance by;
repeatedly applying a predetermined voltage to the measurable capacitance;
repeatedly sharing charge between the measurable capacitance and an integrating capacitance to accumulate charge on the integrating capacitance;
repeatedly measuring voltage on the integrating capacitance and generating quantized values responsive to the repeated measurings;
repeatedly changing charge on the integrating capacitance based on the quantized values; and
determining the capacitance value of the measurable capacitance from the quantized values; and
b) computer readable media bearing the proximity sensor program.
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Accused Products
Abstract
Methods, systems and devices are described for detecting a measurable capacitance using sigma-delta measurement techniques. According to various embodiments, a voltage is applied to the measurable capacitance using a first switch. The measurable capacitance is allowed to share charge with a passive network. If the charge on the passive network is past a threshold value, then the charge on the passive network is changed by a known amount for a sufficient number of repetitions until the measurable capacitance can be detected. Such a detection scheme may be readily implemented using conventional components, and can be particularly useful in sensing the position of a finger, stylus or other object with respect to a button, slider, touchpad or other input sensor.
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Citations
19 Claims
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1. A program product comprising:
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a) a proximity sensor program configured to determine a capacitance value of a measurable capacitance by; repeatedly applying a predetermined voltage to the measurable capacitance; repeatedly sharing charge between the measurable capacitance and an integrating capacitance to accumulate charge on the integrating capacitance; repeatedly measuring voltage on the integrating capacitance and generating quantized values responsive to the repeated measurings; repeatedly changing charge on the integrating capacitance based on the quantized values; and determining the capacitance value of the measurable capacitance from the quantized values; and b) computer readable media bearing the proximity sensor program. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A program product comprising:
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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 second capacitance is past a threshold; changing a charge on the second 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. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A controller including a memory, the memory including executable instructions for determining a capacitance value of a first capacitance by performing the steps of:
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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. - View Dependent Claims (16, 17, 18, 19)
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Specification