6.8 A pen-pressure-sensitive capacitive touch system using electrically coupled resonance pen

Park, Changbyung; Kim, Ki-duk; Park, Sang-hui; Park, Juwan; Huh, Yunhee; Kang, Byunghoon; Cho, Gyu‐Hyeong

doi:10.1109/isscc.2015.7062957

Cited by 21 publications

(10 citation statements)

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“…The power consumption is lower than those presented in [ 12 , 20 , 21 ]. The chip area is smaller than the reported results [ 12 , 21 , 22 ]. To obtain a high SNR and scan rate, the OFDM sensing scheme is proposed and the SNR of this chip attains up to 60 dB.…”

Section: Resultscontrasting

confidence: 57%

“…To obtain a high SNR and scan rate, the OFDM sensing scheme is proposed and the SNR of this chip attains up to 60 dB. Contrary to the conventional structure for the touch panel in [ 12 , 20 , 21 , 22 ], the mixer, VGA, and HPF are proposed in the AFE. The AFE of [ 12 , 20 , 21 , 22 ] is composed of integrators, but this paper proposes the mixer and VGA instead of integrators.…”

Section: Resultsmentioning

confidence: 99%

“…Contrary to the conventional structure for the touch panel in [ 12 , 20 , 21 , 22 ], the mixer, VGA, and HPF are proposed in the AFE. The AFE of [ 12 , 20 , 21 , 22 ] is composed of integrators, but this paper proposes the mixer and VGA instead of integrators. Therefore, the touch signal processing time in the AFE is faster and higher than in [ 12 , 20 , 21 , 22 ].…”

Section: Resultsmentioning

confidence: 99%

“…The AFE of [ 12 , 20 , 21 , 22 ] is composed of integrators, but this paper proposes the mixer and VGA instead of integrators. Therefore, the touch signal processing time in the AFE is faster and higher than in [ 12 , 20 , 21 , 22 ]. Therefore, the proposed structure has a SNR of 60 dB and a frame rate of 200 Hz to scan the 28 × 16 channel capacitive touch panel.…”

Section: Resultsmentioning

confidence: 99%

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A High Noise Immunity, 28 × 16-Channel Finger Touch Sensing IC Using OFDM and Frequency Translation Technique

Kim

Rikan

et al. 2018

Sensors

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In this paper, a high noise immunity, 28 × 16-channel finger touch sensing IC for an orthogonal frequency division multiplexing (OFDM) touch sensing scheme is presented. In order to increase the signal-to-noise ratio (SNR), the OFDM sensing scheme is proposed. The transmitter (TX) transmits the orthogonal signal to each channels of the panel. The receiver (RX) detects the magnitude of the orthogonal frequency to be transmitted from the TX. Due to the orthogonal characteristics, it is robust to narrowband interference and noise. Therefore, the SNR can be improved. In order to reduce the noise effect of low frequencies, a mixer and high-pass filter are proposed as well. After the noise is filtered, the touch SNR attained is 60 dB, from 20 dB before the noise is filtered. The advantage of the proposed OFDM sensing scheme is its ability to detect channels of the panel simultaneously with the use of multiple carriers. To satisfy the linearity of the signal in the OFDM system, a high-linearity mixer and a rail-to-rail amplifier in the TX driver are designed. The proposed design is implemented in 90 nm CMOS process. The SNR is approximately 60 dB. The area is 13.6 mm2, and the power consumption is 62.4 mW.

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Section: Resultscontrasting

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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A High Noise Immunity, 28 × 16-Channel Finger Touch Sensing IC Using OFDM and Frequency Translation Technique

Kim

Rikan

et al. 2018

Sensors

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“…Nevertheless, the number of front-end analog circuits needs to be carefully estimated to prevent an unnecessary waste. On the other hand, the parallel driving method [10], [12]- [15] is also extensively applied in industry to get a better signal-to-noise ratio (SNR). As the number of parallel driving channels is larger, the SNR is better.…”

Section: Introductionmentioning

confidence: 99%

Frequency Hopping and Parallel Driving With Random Delay Especially Suitable for the Charger Noise Problem in Mutual-Capacitive Touch Applications

2019

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Charger noise can cause inaccurate touch points and fake touch points to appear; this can cause a device to behave incorrectly. The intensity of charger noise could be much larger than the intensities of the original touch signals. Furthermore, the frequency of charger noise varies for each different charger. Therefore, industry experts have identified charger noise as the most difficult problem in capacitive touch applications. The demand for a solution to this problem has become crucial for the mobile market. In this paper, we prove that a particular combination of frequency hopping and repeated integration is an effective method to handle this problem. In addition, we propose an efficient discrete Fourier transform-based algorithm to select an effective sensing frequency. We propose parallel driving with random delay to enhance the signal-to-noise ratio (SNR). We show an efficient hardware-software co-design that facilitates the application of our methods in touch ICs. The experimental results show that our methods can increase SNR by over 45 dB and can find an effective sensing frequency fast and dynamically.INDEX TERMS Charger noise, parallel driving, frequency hopping, repeated integration, mutual-capacitive touch.

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Adiabatically driven touch controller analog front-end for ultra-thin displays

Park

Hwang

et al. 2018

2018 IEEE Custom Integrated Circuits Conference (CICC)

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6.8 A pen-pressure-sensitive capacitive touch system using electrically coupled resonance pen

Cited by 21 publications

References 1 publication

A High Noise Immunity, 28 × 16-Channel Finger Touch Sensing IC Using OFDM and Frequency Translation Technique

A High Noise Immunity, 28 × 16-Channel Finger Touch Sensing IC Using OFDM and Frequency Translation Technique

Frequency Hopping and Parallel Driving With Random Delay Especially Suitable for the Charger Noise Problem in Mutual-Capacitive Touch Applications

Adiabatically driven touch controller analog front-end for ultra-thin displays

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