Multiple simultaneous frequency detection
First Claim
1. A method for obtaining a plurality of values used to generate an image of touch from a touch sensor panel, comprising:
- simultaneously applying a plurality of stimulation frequencies having positive and negative phases to a plurality of drive lines of the touch sensor panel in a particular distribution;
receiving a signal from each of a plurality of sense lines of the touch sensor panel into a different sense channel;
demodulating the signal received into each sense channel with a plurality of demodulation frequencies, the demodulation frequencies being the same frequencies as the stimulation frequencies but in-phase;
accumulating the signals demodulated with the plurality of demodulation frequencies in each sense channel to generate a plurality of values representing the accumulated demodulated signals for each sense channel; and
storing the plurality of values for all sense channels.
3 Assignments
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Accused Products
Abstract
The use of multiple stimulation frequencies and phases to generate an image of touch on a touch sensor panel is disclosed. Each of a plurality of sense channels can be coupled to a column in a touch sensor panel and can have multiple mixers. Each mixer in the sense channel can utilize a circuit capable generating a demodulation frequency of a particular frequency. At each of multiple steps, various phases of selected frequencies can be used to simultaneously stimulate the rows of the touch sensor panel, and the multiple mixers in each sense channel can be configured to demodulate the signal received from the column connected to each sense channel using the selected frequencies. After all steps have been completed, the demodulated signals from the multiple mixers can be used in calculations to determine an image of touch for the touch sensor panel at each frequency.
298 Citations
33 Claims
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1. A method for obtaining a plurality of values used to generate an image of touch from a touch sensor panel, comprising:
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simultaneously applying a plurality of stimulation frequencies having positive and negative phases to a plurality of drive lines of the touch sensor panel in a particular distribution; receiving a signal from each of a plurality of sense lines of the touch sensor panel into a different sense channel; demodulating the signal received into each sense channel with a plurality of demodulation frequencies, the demodulation frequencies being the same frequencies as the stimulation frequencies but in-phase; accumulating the signals demodulated with the plurality of demodulation frequencies in each sense channel to generate a plurality of values representing the accumulated demodulated signals for each sense channel; and storing the plurality of values for all sense channels. - View Dependent Claims (2, 3, 4, 5)
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6. In a system including a sensor panel having a plurality of drive lines being simultaneously driven with a plurality of stimulation frequencies having positive and negative phases in a particular distribution, a method for obtaining a plurality of values used to generate an image of touch, the method comprising:
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demodulating a sense signal received on each sense line of the sensor panel with a plurality of demodulation frequencies, the demodulation frequencies being the same frequencies as the stimulation frequencies but in-phase; and accumulating each of the plurality of demodulated sense signals for each sense line to generate the plurality of values representing the accumulated demodulated sense signals. - View Dependent Claims (7, 8, 9, 10)
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11. An apparatus for obtaining a plurality of values used to generate an image of touch from a touch sensor panel, comprising:
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a plurality of sense channels, each sense channel including a charge amplifier configured for receiving a signal from a different sense line of the touch sensor panel, a plurality of mixers coupled to an output of the multiplexer, one frequency generator circuit coupled to each of the plurality of mixers for generating a demodulation frequency, and one accumulator coupled to each of the plurality of mixers for generating a value representing an accumulated mixer output; wherein each frequency generator circuit in each sense channel generates a different demodulation frequency, the different demodulation frequencies corresponding to different stimulation frequencies simultaneously applied with different phases to drive lines of the touch sensor panel. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method for operating a touchscreen, the touchscreen having a touch sensor panel and a display device, the method comprising:
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updating the display device during an active period of the display device; and obtaining an image of touch from the touch sensor panel during a vertical blanking phase of the display device. - View Dependent Claims (19)
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20. A system for obtaining a plurality of values from a touch sensor panel, the plurality of values for generating an image of touch, the system comprising:
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a touch sensor panel having a plurality of drive lines and a plurality of sense lines; and an integrated circuit coupled to the touch sensor panel, including driver logic configured for generating a plurality of stimulation signals to the plurality of drive lines, the driver logic including a charge pump configured for converting a low level supply voltage for the integrated circuit into a higher level supply voltage, the driver logic further configured for converting the higher level supply voltage into reduced amplitude stimulation signals, and a plurality of sense channels, each sense channel including a charge amplifier configured for receiving a sense signal from a different sense line of the touch sensor panel, the plurality of sense channels for generating the plurality of values from the received sense lines, the plurality of values representing a plurality of accumulated mixer outputs; wherein each charge amplifier in each sense channel includes a reduced feedback capacitance whose physical size is scaled down in accordance with a lower amount of charge injected onto the sense lines by the reduced amplitude stimulation signals. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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28. A method for obtaining a plurality of values from a touch sensor panel, the plurality of values for generating an image of touch, the method comprising:
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utilizing a charge pump within an integrated circuit to convert a low level supply voltage for the integrated circuit into a higher level voltage, utilizing the higher level voltage to generate reduced amplitude stimulation signals within the integrated circuit, the reduced amplitude stimulation signals for driving a plurality of drive lines in a touch sensor panel; receiving a sense signal from each of a plurality of sense lines in the touch sensor panel into a charge amplifier in each of a plurality of sense channels within the integrated circuit, the plurality of sense channels for generating the plurality of values from the received sense signals, the plurality of values representing a plurality of accumulated mixer outputs; and utilizing a reduced feedback capacitance in each charge amplifier whose physical size is scaled down in accordance with a lower amount of charge injected onto the sense lines by the reduced amplitude stimulation signals. - View Dependent Claims (29, 30, 31)
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32. A mobile telephone including an apparatus for obtaining a plurality of values used to generate an image of touch from a touch sensor panel, the apparatus comprising:
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a plurality of sense channels, each sense channel including a charge amplifier configured for receiving a signal from a different sense line of the touch sensor panel, a plurality of mixers coupled to an output of the multiplexer, one frequency generator circuit coupled to each of the plurality of mixers for generating a demodulation frequency, and one accumulator coupled to each of the plurality of mixers for generating a value representing an accumulated mixer output; wherein each frequency generator circuit in each sense channel generates a different demodulation frequency, the different demodulation frequencies corresponding to different stimulation frequencies simultaneously applied with different phases to drive lines of the touch sensor panel.
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33. A digital audio player including an apparatus for obtaining a plurality of values used to generate an image of touch from a touch sensor panel, the digital audio player comprising:
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a plurality of sense channels, each sense channel including a charge amplifier configured for receiving a signal from a different sense line of the touch sensor panel, a plurality of mixers coupled to an output of the multiplexer, one frequency generator circuit coupled to each of the plurality of mixers for generating a demodulation frequency, and one accumulator coupled to each of the plurality of mixers for generating a value representing an accumulated mixer output; wherein each frequency generator circuit in each sense channel generates a different demodulation frequency, the different demodulation frequencies corresponding to different stimulation frequencies simultaneously applied with different phases to drive lines of the touch sensor panel.
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Specification