A Low-Computing-Complexity Touch Signal Detection Method and Analog Front-End Circuits Based on Cross-Correlation Technology for Large-Size Touch Panel
Abstract
:1. Introduction
- A novel cross-correlation operation AFE architecture and analog cross-correlation computing circuits are proposed;
- The proposed cross-correlation AFE method achieved the detection of the weak touch signal submerged in the large display panel noise;
- The proposed cross-correlation multi-frequency driving AFE realizes a high frame rate without complex FFT circuits to reduce the die area and power consumption;
- The proposed touch signal detection method only samples and processes the signals around the touch points rather than full-screen data to decrease the computing complexity and ADC acquisition number.
2. Channel Difference and Cross-Correlation Analysis
2.1. Channel Difference Analysis
2.2. Cross-Correlation Analysis
3. The Proposed Low-Computing-Complexity Acquisition Analog Front-End
3.1. The Architecture of the Proposed Low-Computing-Complexity AFE
- Step 1: The cross-correlation operation of the RX signal and RX signal passing through the symbol function realizes the on/off judgment function of the touch point of the RX channel;
- Step 2: The cross-correlation operations of the RX signal with the touch point and each TX signal realize the on/off judgment function of the touch point of the TX channel. Rough touch point coordinates are obtained after the above two steps;
- Step 3: The cross-correlation values around the touch point are sampled precisely by the 12-bit SAR-VCO ADC and sent to MCU;
- Step 4: The touch point coordinates are accurately calculated with MCU and mapped to display coordinates.
3.2. The Circuit Implementation of the Proposed Cross-Correlation AFE
3.2.1. The RX Judgment Circuit
3.2.2. The TX Judgment Circuit
3.2.3. The Precise Cross-Correlation Sample Circuit
4. Results and Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Parameters | JSSC 2019 [12] | CAS-I 2020 [11] | Sensors J. 2019 [32] | JSSC 2021 [24] | Sensors 2020 [14] | This Work |
---|---|---|---|---|---|---|
Process | 0.18 μm | 0.13 μm | 0.13 μm | 0.18 μm | 0.35 μm | 0.11 μm |
Supply | 3.3 V | 3 V | 3.3/20 V | 3.3 V | 3.3 V | 1.2/3.3 V |
Frame Rate | 120 Hz | 240 Hz | 120 Hz | 120 Hz | 250 Hz | ~3846 Hz@ 1 point; ~384.6 Hz@ 10 points |
Channels | TX: 36; RX: 64 | TX: 31; RX: 15 | 128 × 72 | TX: 8; RX: 17 | TX: 15; RX: 12 | TX: 32; RX: 32 |
Total Channels | 100 | 46 | 200 | 25 | 27 | 62 |
Power | 94.5 mW | 11.5 mW | 65.31 mW | 12 mW | 10.4 mW | 14.55 mW |
Average Power | 0.945 mW/channel | 0.25 mW/channel | 0.327 mW/channel | 0.48 mW/channel | 0.385 mW/channel | 0.227 mW/channel |
Active Area | 36 mm2 | 1.49 mm2 | 56.25 mm2 | 3.04 mm2 | 4.1 mm2 | 0.988 mm2 |
Average Area | 0.36 mm2/channel | 0.032 mm2/channel | 0.281 mm2/channel | 0.122 mm2/channel | 0.152 mm2/channel | 0.015 mm2/channel |
SNR | 54 dB | 54.2 dB | 47.8 dB | 37.5 dB | 41 dB | 46.1 dB |
Application | 12.2 inch | 5.3 inch | 32 inch | 6.7 inch | N/A | 65 inch |
ADC Number | 32 | 31 | 128 | 1 (shared) | 5 | 1 |
Computing Complexity | MN | MN | MN | MN | MN | M + nN |
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Guo, X.; Li, H.; Chen, Y.; Sun, W. A Low-Computing-Complexity Touch Signal Detection Method and Analog Front-End Circuits Based on Cross-Correlation Technology for Large-Size Touch Panel. Sensors 2022, 22, 4354. https://doi.org/10.3390/s22124354
Guo X, Li H, Chen Y, Sun W. A Low-Computing-Complexity Touch Signal Detection Method and Analog Front-End Circuits Based on Cross-Correlation Technology for Large-Size Touch Panel. Sensors. 2022; 22(12):4354. https://doi.org/10.3390/s22124354
Chicago/Turabian StyleGuo, Xiaoyu, Hongge Li, Yuhao Chen, and Wei Sun. 2022. "A Low-Computing-Complexity Touch Signal Detection Method and Analog Front-End Circuits Based on Cross-Correlation Technology for Large-Size Touch Panel" Sensors 22, no. 12: 4354. https://doi.org/10.3390/s22124354