Invention Grant
- Patent Title: System for and method of transferring charge to convert capacitance to voltage for touchscreen controllers
- Patent Title (中): 用于将电荷转换为触摸屏控制器的电容的系统和方法
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Application No.: US12986841Application Date: 2011-01-07
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Publication No.: US08624870B2Publication Date: 2014-01-07
- Inventor: Ashutosh Ravindra Joharapurkar , Karthikeya Kodur , Venugopal Reddy , Patrick Chan
- Applicant: Ashutosh Ravindra Joharapurkar , Karthikeya Kodur , Venugopal Reddy , Patrick Chan
- Applicant Address: US CA San Jose
- Assignee: Maxim Integrated Products, Inc.
- Current Assignee: Maxim Integrated Products, Inc.
- Current Assignee Address: US CA San Jose
- Agency: Advent, LLP
- Main IPC: G06F3/045
- IPC: G06F3/045

Abstract:
A touchscreen controller system determines the actual locations of multiple simultaneous touches by eliminating mutual capacitance between adjacent rows and columns during self-capacitance measurements and selectively enabling mutual capacitance during mutual capacitance measurements. During the self-capacitance measurements, the controller system generates a set of candidate touch locations, which includes the locations of real and ghost touches. During the mutual capacitance measurements, only the locations in the candidate set are measured and, from these measurements, the actual touch locations are determined. By limiting the mutual capacitive measurements to only a small subset of the locations over the entire touch panel, real touch locations are determined on a linear order. Also, by using on-chip integration capacitors, embodiments of the invention are able to perform each measurement in a single cycle.
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