Abstract
This article presents a readout integrated circuit (ROIC) for capacitive touch-screen panels (TSPs) employing an amplitude-modulated multiple-frequency excitation (AM-MFE) technique. To prevent charge overflow, which occurs periodically at the beat frequency of the excitation frequencies, the ROIC modulates the amplitude of the excitation voltages at a mixing frequency derived from the excitation frequencies. Thus, the ROIC can sense the charge signal without charge overflow and maximize the signal-to-noise ratio (SNR) by increasing the amplitude of the excitation voltages up to the sensing range of the readout circuit. The proposed ROIC was fabricated in a 0.13- $\mu \text{m}$ standard CMOS process and was measured with a 32-in 104 $\times $ 64 touch-screen panel using 1 and 10 mm metal pillars. It reduces charge overflow up to 33.9 dB compared to operation without AM-MFE. In addition, the ROIC achieves a frame rate of 2.93 kHz, and SNRs of 41.7 and 61.6 dB with 1 and 10 mm metal pillars, respectively.
Original language | English |
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Pages (from-to) | 3486-3498 |
Number of pages | 13 |
Journal | IEEE Journal of Solid-State Circuits |
Volume | 56 |
Issue number | 11 |
DOIs | |
Publication status | Published - 2021 |
Bibliographical note
Accepted Author ManuscriptKeywords
- Amplitude-modulated multi-frequency excitation (AM-MFE)
- capacitive touch system (CTS)
- charge overflow reduction
- frame rate
- readout IC (ROIC)
- signal-to-noise ratio (SNR)
- touch screen panel (TSP).