11.6 A 100-TRX-channel configurable 85-to-385Hz-frame-rate analog front-end for touch controller with highly enhanced noise immunity of 20Vpp

Park, Jun Eun; Park, Jiheon; Hwang, Young‐Ha; Oh, Jonghyun; Jeong, Deog‐Kyoon

doi:10.1109/isscc.2016.7417981

Cited by 17 publications

(6 citation statements)

References 3 publications

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“…By repeatedly alternating the CA output pairs using the 3:2 MUX, the number of DPGAs can be reduced by nearly half [ 14 ]. The differential sensing scheme can not only eliminate the noise common to Rx channels, such as the display and internal bias noise, but also alleviate the newly introduced noise by the NC circuit [ 6 ]. The outputs of the upper DPGA in Figure 8 are demodulated with an in-phase clock that has the same triggering edge as the Tx driving pulse, and the outputs of the lower DPGA are demodulated with a clock that is shifted 90° compared to the in-phase clock.…”

Section: Full Chip Implementationmentioning

confidence: 99%

“…The mesh-shape of the sensor electrode can reduce the coupling capacitance between the sensor and display electrodes, and its low resistance can compensate for the effect of the increased capacitance in terms of the bandwidth of the LPF. Nevertheless, in TSCs that use a charge amplifier (CA) scheme because of its excellent immunity to low-frequency noises, the frequency characteristics of the amplifier in the CA stage can limit the bandwidth of the touch sensor [ 2 , 4 , 5 , 6 , 7 ]. This will be discussed in more detail in Section 2 .…”

Section: Introductionmentioning

confidence: 99%

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Mutual Capacitive Sensing Touch Screen Controller for Ultrathin Display with Extended Signal Passband Using Negative Capacitance

Lee

Park

Piao

et al. 2018

Sensors

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Flexible and thin displays for smart devices have a large coupling capacitance between the sensor electrode of the touch screen panel (TSP) and the display electrode. This increased coupling capacitance limits the signal passband to less than 100 kHz, resulting in a significant reduction in the received signal, with a driving frequency of several hundred kilohertz used for noise avoidance. To overcome this problem, we reduced the effective capacitance at the analog front-end by connecting a circuit with a negative capacitance in parallel with the coupling capacitance of the TSP. In addition, the in-phase and quadrature demodulation scheme was used to address the phase fluctuation between the signal and the clock during demodulation. We fabricated a test chip using the 0.35 µm CMOS process and obtained a signal-to-noise ratio of 43.2 dB for a 6 mm diameter metal pillar touch input.

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Section: Full Chip Implementationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mutual Capacitive Sensing Touch Screen Controller for Ultrathin Display with Extended Signal Passband Using Negative Capacitance

Lee

Park

Piao

et al. 2018

Sensors

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show abstract

“…There are a few papers proposed to resolve the noise problem [4]- [10]. They all presented that repeated integration is an effective method for this problem.…”

Section: Introductionmentioning

confidence: 99%

“…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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“…The popularity of using touch screen in current commercial electronic devices has boosted the touch related research in both academy and industry. Among the reported works, majority of the work are about how to extract accurate finger position on the noisy tight touch space with relative low power consumption [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Galaxies at z ~ 6: physical properties at the edge of the cosmic reionization

Barros¹,

Vanzella²,

Pentericci

et al. 2015

Proc. IAU

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Abstract-Touch sensing, as a major human/machine interface, is widely used in various commercial products such as smart watches, mobile phones, tablets and TVs. State-of-the-art touch detections are mainly based on mutual capacitive sensing, which requires necessary contact-touch, limiting the mobile user experience. Recently, remote gesture sensing is widely reported in both academy and industry as it can provide additional userexperience for mobile interface. The capacitive remote gesture sensing is mainly based on detecting self-capacitance, achieving high resolution through eliminating the parasitic mutual capacitance. In this work, we overview the different generations of touchscreen technology, comparing the touch and remote gesture sensing technologies difference. In addition, different remote gesture sensing technologies are also compared. The limitations and potentials of different topologies are discussed and a final conclusion about the technology trends is summarized in the end.

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11.6 A 100-TRX-channel configurable 85-to-385Hz-frame-rate analog front-end for touch controller with highly enhanced noise immunity of 20Vpp

Cited by 17 publications

References 3 publications

Mutual Capacitive Sensing Touch Screen Controller for Ultrathin Display with Extended Signal Passband Using Negative Capacitance

Mutual Capacitive Sensing Touch Screen Controller for Ultrathin Display with Extended Signal Passband Using Negative Capacitance

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

Galaxies at z ~ 6: physical properties at the edge of the cosmic reionization

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