A Sensing Mode Reconfigurable Analog Front-End IC for Capacitive Touch and a-IGZO TFT-Based Active-Matrix Capacitive Fingerprint Sensors

Jae Sung An, Sang Hyun Han, Jae Hun Ye

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)

Abstract

In this paper, we propose a sensing mode reconfigurable analog front-end (AFE) IC for a capacitive touch sensor (CTS) and amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT)-based active-matrix capacitive fingerprint sensor (CFS). The CTS consists of the transmit and receive electrodes for enabling the mutual-capacitance (CM) sensing mode, which can detect the multi-touch. The CFS has the array of a-IGZO TFT and a sensing electrode for enabling the self-capacitance (CS) sensing mode to achieve the high sensitivity. In addition, it can reduce the number of sensing lines by adopting the active-matrix type structure to achieve the low-manufacturing cost. To sense the CTS and CFS, the proposed AFE IC is reconfigured to operate the CM and CS sensing modes, respectively. The proposed AFE IC was fabricated using a 0.13μm CMOS process technology with 20 V high-voltage devices, and demonstrated with a 128× 72 32 -inch CTS and a 96× 96 0.27 -inch CFS, which represents a pixel resolution of 500 pixel-per-inch. The proposed AFE IC achieves the signal-to-noise ratios of 47.8 dB and 25.0 dB for the CTS and CFS, respectively.

Original languageEnglish
Article number8798746
Pages (from-to)11544-11552
Number of pages9
JournalIEEE Sensors Journal
Volume19
Issue number23
DOIs
Publication statusPublished - 1 Dec 2019
Externally publishedYes

Keywords

  • a-IGZO TFT-based capacitive fingerprint sensor
  • Analog front-end (AFE) IC
  • capacitive touch sensor
  • self- and mutual-capacitance sensing modes

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