A Capacitive Touch Chipset with 33.9dB Charge-Overflow Reduction Using Amplitude-Modulated Multi-Frequency Excitation and Wireless Power and Data Transfer to an Active Stylus

Jae Sung An, Jong Hyun Ra, Eunchul Kang, Michiel A.P. Pertijs, Sang Hyun Han

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

Abstract

As the demand for high frame rate and SNR increases in capacitive touch systems (CTSs), several driving methods have been reported [1], [5]. However, when excitation circuits simultaneously send excitation signals VEXTs to multiple TX electrodes in order to increase frame rate, the readout circuit suffers from charge overflow because of the superposition of VEXTs. To prevent this, driving methods such as time-division [1], [5] and reduced-amplitude excitation [3], and signal omitting and linear interpolation in the digital domain [4] have been adopted in AFE ICs, but they degrade the frame rate, and SNR, and increase the computational load of the CTS, respectively. In this paper, amplitude-modulated multiple-frequency excitation (AM-MFE) is used to prevent charge overflow without degrading the frame rate, SNR, and computational load. In addition, an electric pencil case (EPC) is proposed for wireless power and data transfer to an active stylus, so as to avoid the need to replace the battery of the stylus or charge it via an adapter.

Original languageEnglish
Title of host publication2020 IEEE International Solid-State Circuits Conference, ISSCC 2020
PublisherIEEE
Pages430-432
Number of pages3
ISBN (Electronic)978-1-7281-3205-1
ISBN (Print)978-1-7281-3206-8
DOIs
Publication statusPublished - 2020
Event2020 IEEE International Solid-State Circuits Conference, ISSCC 2020 - San Francisco, United States
Duration: 16 Feb 202020 Feb 2020

Conference

Conference2020 IEEE International Solid-State Circuits Conference, ISSCC 2020
CountryUnited States
CitySan Francisco
Period16/02/2020/02/20

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