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.

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.

Abstract: Methods, systems and devices are described for detecting a measurable capacitance using charge transfer techniques. According to various embodiments, a charge transfer process is performed for two or more times. During the charge transfer process, a pre-determined voltage is applied to the measurable capacitance, and the measurable capacitance is then allowed to share charge with a filter capacitance through a passive impedance that remains coupled to both the measurable capacitance and to the filter capacitance throughout the charge transfer process. The value of the measurable capacitance can then be determined as a function of a representation of a charge on the filter capacitance and the number of times that the charge transfer process was performed. 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 an input sensor.

Abstract: Methods, systems and devices are described for detecting noise in a touchpad or other sensor that produces an output in response to a stimulus that is applied at or near a sensing region. According to various embodiments, a carrier signal is applied to the sensing region at two or more frequencies to thereby produce an output from the sensing region at each frequency. Each of the outputs is demodulated and filtered by a demodulation filter having a demodulation filter bandwidth. The various frequencies applied to the carrier signal are selected such that a difference between the frequencies is less than the demodulation filter bandwidth. At least some of the effects of the stimulus are removed from the outputs produced by the various carrier frequencies to produce two or more filtered outputs. The filtered outputs are then added, combined or otherwise processed to detect noise contained therein.

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.

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.

Abstract: Methods, systems and devices are described for detecting a measurable capacitance using charge transfer techniques. According to various embodiments, a charge transfer process is performed for two or more times. During the charge transfer process, a pre-determined voltage is applied to the measurable capacitance, and the measurable capacitance is then allowed to share charge with a filter capacitance through a passive impedance that remains coupled to both the measurable capacitance and to the filter capacitance throughout the charge transfer process. The value of the measurable capacitance can then be determined as a function of a representation of a charge on the filter capacitance and the number of times that the charge transfer process was performed. 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 an input sensor.

Abstract: Methods and apparatus are provided for measuring a ratio of capacitances.

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.

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.

Abstract: Methods, systems and devices are described for detecting noise in a touchpad or other sensor that produces an output in response to a stimulus that is applied at or near a sensing region. According to various embodiments, a carrier signal is applied to the sensing region at two or more frequencies to thereby produce an output from the sensing region at each frequency. Each of the outputs is demodulated and filtered by a demodulation filter having a demodulation filter bandwidth. The various frequencies applied to the carrier signal are selected such that a difference between the frequencies is less than the demodulation filter bandwidth. At least some of the effects of the stimulus are removed from the outputs produced by the various carrier frequencies to produce two or more filtered outputs. The filtered outputs are then added, combined or otherwise processed to detect noise contained therein.