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Capacitive touch sensing system using switched capacitor analog signal processing

A touch sensing, capacitor technology, applied in electrical digital data processing, data processing input/output process, instruments, etc., can solve the problems of analog-to-digital converter signal loss, unrecoverable, increased component cost and component cost, etc.

Inactive Publication Date: 2018-04-20
UICO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The cost of analog-to-digital components plus digital signal processing components can add significantly to the part cost and component cost of the finished product
Second, if the signal processing is done in the digital domain, any signal below the least significant bit from the analog-to-digital converter will be lost and cannot be recovered

Method used

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  • Capacitive touch sensing system using switched capacitor analog signal processing
  • Capacitive touch sensing system using switched capacitor analog signal processing
  • Capacitive touch sensing system using switched capacitor analog signal processing

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Embodiment Construction

[0037] Capacitive touch sensing systems can be divided into two categories, self-capacitance-based systems and mutual-capacitance-based systems. In self-capacitance-based systems, the capacitance of the sensor is measured with respect to ground. In mutual capacitance based systems, the capacitance of a pair of sensors is measured. Both types of systems can be found in devices such as smartphones, tablets, and other electronic devices.

[0038] In theory, the self-capacitance of a conducting electrode is the capacitance of an electrode isolated such that all other conductors and charged surfaces are infinitely far away. In fact, it is impossible to have completely isolated conductors in space. The self-capacitance of the conductor or sensor is increased by other adjacent conductors such as signal lines, metal housings and stackups forming the capacitive sensor substrate. Thus, in touch sensing technology, self-capacitance refers to the capacitance of a sensor electrode relat...

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Abstract

A capacitive touch sensing system for a capacitive touch panel uses analog circuitry to perform capacitive sensing and signal processing. The system operates over several time phases to charge and discharge a capacitive sensor of the touch panel and determine capacitance of the capacitive sensor. The system actively reconfigures and reuses circuit components over the several phases to minimize a circuit size, complexity and power usage. The chip area is greatly reduced by performing major signal processing functions in a small piece of analog circuitry. The cost is reduced by combining the signal processing functions into a small, time-sequenced switched-capacitor analog circuit.

Description

technical field [0001] The present invention relates to capacitive touch sensing systems. More specifically, the present invention relates to capacitive touch sensing systems using switched capacitor signal processing. Background technique [0002] Capacitive touch sensors are often used in combination with a display, such as a liquid crystal display (LCD), to provide a user interface for an electronic device such as a smartphone, tablet, or other portable device. LCDs can be used to provide textual and graphical information to the user. Capacitive touch sensors can be used to sense a user's touch interaction with a device, including sensing motions such as taps, swipes, and rotations of a finger, stylus, or other object on the surface of the touch sensor. In other applications, touch sensors are used alone to receive user input without an LCD or other display. [0003] Design requirements for capacitive touch sensors include low cost and immunity to noise and other elect...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F3/044
CPCG06F3/044G06F3/04166G06F3/04182G06F3/0446
Inventor 乔蒂德拉·萨迦肯尼思·C.克兰德尔赫特·辛格·兰德哈瓦
Owner UICO