The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
Masayuki Miyamoto - One of the best experts on this subject based on the ideXlab platform.
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6 6 a 240hz reporting rate Mutual Capacitance touch sensing analog front end enabling multiple active passive styluses with 41db 32db snr for 0 5mm diameter
International Solid-State Circuits Conference, 2015Co-Authors: Mutsumi Hamaguchi, Michiaki Takeda, Masayuki MiyamotoAbstract:A Mutual-Capacitance touch-sensing architecture and a system that enables concurrent usage of multiple active styluses having different properties such as color, thickness, shape, etc., are developed and verified with use of an existing touch controller [1]. An extension of the architecture to handle wireless active styluses is also developed and verified with an analog front-end (AFE) IC.
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a 143 times 81 Mutual Capacitance touch sensing analog front end with parallel drive and differential sensing architecture
IEEE Journal of Solid-state Circuits, 2015Co-Authors: Masayuki Miyamoto, Mutsumi Hamaguchi, Akira NagaoAbstract:This paper presents an analog front-end (AFE) IC for Mutual Capacitance touch sensing with 224 sensor channels in 0.18 $~\mu\hbox{m}$ CMOS with 3.3 V drive voltage. A 32-in touch sensing system and a 70-in one having 37 dB SNR for 1 mm diameter stylus at 240 Hz reporting rate are realized with the AFE. The AFE adopts a parallel drive method to achieve the large format and the high SNR simultaneously. With the parallel drive method, the measured SNRs of the AFE stay almost constant at a higher level regardless of the number of sensor channels, which was impossible by conventional sequential drive methods. A novel differential sensing scheme which enhances the immunity against the noise from a display device is also realized in the AFE. While the coupled LCD is on and off, the differences between the measured SNRs are less than 2 dB.
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an 87 49 Mutual Capacitance touch sensing ic enabling 0 5 mm diameter stylus signal detection at 240 hz reporting rate with palm rejection
Asian Solid-State Circuits Conference, 2014Co-Authors: Shinichi Yoshida, Mutsumi Hamaguchi, Akira Nagao, Takahiro Morishita, Shinji Shinjo, Masayuki MiyamotoAbstract:A touch sensing system capable of stylus input should have “palm rejection” function which allows the user to place one's palm on the surface of the touch sensor while writing with a stylus. In order to realize “palm rejection”, it is necessary to detect the small stylus while neglecting large signal from the palm. However this is not sufficient because small electrical noise injected through the palm into the touch sensor impedes stylus input signal in real use. This issue is because the injected noise propagates onto the touch sensor's sense channels which are capacitively-coupled with the palm and degrades the SNR of the stylus signal on the channels. A simple and effective technique to eliminate this issue is implemented in a newly developed 87×49 Mutual Capacitance touch sensing IC which is fabricated in an 85 nm CMOS technology. It achieves an SNR over 33 dB for a 0.5 mm-diameter stylus when a 10 Vp-p sinusoidal noise is injected to the stylus and the palm. Both the die area and the power consumption of a unit charge-to-voltage converter (CVC) designed for the IC are reduced to approximately 50% compared to those of the previous implementation [4]. In order not to report unwanted touches due to palm signals, a palm detection filter is implemented in the digital signal processor on the IC.
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12 3 a 240hz reporting rate 143 81 Mutual Capacitance touch sensing analog front end ic with 37db snr for 1mm diameter stylus
International Solid-State Circuits Conference, 2014Co-Authors: Mutsumi Hamaguchi, Akira Nagao, Masayuki MiyamotoAbstract:Realization of a Mutual-Capacitance touch-sensing system spanning over 30 inches is not a straightforward task, because the SNRs of conventional sequential drive controllers degrade as the number of sensor channels increases. One common way to overcome this drawback is to increase the driving voltage, which however results in an increase in system complexity and cost because it requires high-voltage circuits and devices. This SNR issue is resolved by driving the sensor channels in parallel [1,4] as shown in Fig. 12.3.1. Although the parallel drive mixes up the signals from the multiple channels driven at the same time, the original signals can be reconstructed from the sequence of mixed signals if the drive sequences are linearly independent from each other. By appropriately designing the parallel drive sequences, the SNR is enhanced by √M times compared to that of the sequential drive [1], where M is the number of drive channels. An analog front-end (AFE) IC capable of driving and sensing a 143×81 Mutual-Capacitance sensor is developed in 0.18μm 1P5M CMOS. A 32-inch and a 70-inch touch system are realized with the use of the AFE and an SNR over 37dB for 1mm diameter stylus is attained in either system.
Akira Nagao - One of the best experts on this subject based on the ideXlab platform.
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a 143 times 81 Mutual Capacitance touch sensing analog front end with parallel drive and differential sensing architecture
IEEE Journal of Solid-state Circuits, 2015Co-Authors: Masayuki Miyamoto, Mutsumi Hamaguchi, Akira NagaoAbstract:This paper presents an analog front-end (AFE) IC for Mutual Capacitance touch sensing with 224 sensor channels in 0.18 $~\mu\hbox{m}$ CMOS with 3.3 V drive voltage. A 32-in touch sensing system and a 70-in one having 37 dB SNR for 1 mm diameter stylus at 240 Hz reporting rate are realized with the AFE. The AFE adopts a parallel drive method to achieve the large format and the high SNR simultaneously. With the parallel drive method, the measured SNRs of the AFE stay almost constant at a higher level regardless of the number of sensor channels, which was impossible by conventional sequential drive methods. A novel differential sensing scheme which enhances the immunity against the noise from a display device is also realized in the AFE. While the coupled LCD is on and off, the differences between the measured SNRs are less than 2 dB.
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an 87 49 Mutual Capacitance touch sensing ic enabling 0 5 mm diameter stylus signal detection at 240 hz reporting rate with palm rejection
Asian Solid-State Circuits Conference, 2014Co-Authors: Shinichi Yoshida, Mutsumi Hamaguchi, Akira Nagao, Takahiro Morishita, Shinji Shinjo, Masayuki MiyamotoAbstract:A touch sensing system capable of stylus input should have “palm rejection” function which allows the user to place one's palm on the surface of the touch sensor while writing with a stylus. In order to realize “palm rejection”, it is necessary to detect the small stylus while neglecting large signal from the palm. However this is not sufficient because small electrical noise injected through the palm into the touch sensor impedes stylus input signal in real use. This issue is because the injected noise propagates onto the touch sensor's sense channels which are capacitively-coupled with the palm and degrades the SNR of the stylus signal on the channels. A simple and effective technique to eliminate this issue is implemented in a newly developed 87×49 Mutual Capacitance touch sensing IC which is fabricated in an 85 nm CMOS technology. It achieves an SNR over 33 dB for a 0.5 mm-diameter stylus when a 10 Vp-p sinusoidal noise is injected to the stylus and the palm. Both the die area and the power consumption of a unit charge-to-voltage converter (CVC) designed for the IC are reduced to approximately 50% compared to those of the previous implementation [4]. In order not to report unwanted touches due to palm signals, a palm detection filter is implemented in the digital signal processor on the IC.
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12 3 a 240hz reporting rate 143 81 Mutual Capacitance touch sensing analog front end ic with 37db snr for 1mm diameter stylus
International Solid-State Circuits Conference, 2014Co-Authors: Mutsumi Hamaguchi, Akira Nagao, Masayuki MiyamotoAbstract:Realization of a Mutual-Capacitance touch-sensing system spanning over 30 inches is not a straightforward task, because the SNRs of conventional sequential drive controllers degrade as the number of sensor channels increases. One common way to overcome this drawback is to increase the driving voltage, which however results in an increase in system complexity and cost because it requires high-voltage circuits and devices. This SNR issue is resolved by driving the sensor channels in parallel [1,4] as shown in Fig. 12.3.1. Although the parallel drive mixes up the signals from the multiple channels driven at the same time, the original signals can be reconstructed from the sequence of mixed signals if the drive sequences are linearly independent from each other. By appropriately designing the parallel drive sequences, the SNR is enhanced by √M times compared to that of the sequential drive [1], where M is the number of drive channels. An analog front-end (AFE) IC capable of driving and sensing a 143×81 Mutual-Capacitance sensor is developed in 0.18μm 1P5M CMOS. A 32-inch and a 70-inch touch system are realized with the use of the AFE and an SNR over 37dB for 1mm diameter stylus is attained in either system.
Mutsumi Hamaguchi - One of the best experts on this subject based on the ideXlab platform.
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6 6 a 240hz reporting rate Mutual Capacitance touch sensing analog front end enabling multiple active passive styluses with 41db 32db snr for 0 5mm diameter
International Solid-State Circuits Conference, 2015Co-Authors: Mutsumi Hamaguchi, Michiaki Takeda, Masayuki MiyamotoAbstract:A Mutual-Capacitance touch-sensing architecture and a system that enables concurrent usage of multiple active styluses having different properties such as color, thickness, shape, etc., are developed and verified with use of an existing touch controller [1]. An extension of the architecture to handle wireless active styluses is also developed and verified with an analog front-end (AFE) IC.
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a 143 times 81 Mutual Capacitance touch sensing analog front end with parallel drive and differential sensing architecture
IEEE Journal of Solid-state Circuits, 2015Co-Authors: Masayuki Miyamoto, Mutsumi Hamaguchi, Akira NagaoAbstract:This paper presents an analog front-end (AFE) IC for Mutual Capacitance touch sensing with 224 sensor channels in 0.18 $~\mu\hbox{m}$ CMOS with 3.3 V drive voltage. A 32-in touch sensing system and a 70-in one having 37 dB SNR for 1 mm diameter stylus at 240 Hz reporting rate are realized with the AFE. The AFE adopts a parallel drive method to achieve the large format and the high SNR simultaneously. With the parallel drive method, the measured SNRs of the AFE stay almost constant at a higher level regardless of the number of sensor channels, which was impossible by conventional sequential drive methods. A novel differential sensing scheme which enhances the immunity against the noise from a display device is also realized in the AFE. While the coupled LCD is on and off, the differences between the measured SNRs are less than 2 dB.
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an 87 49 Mutual Capacitance touch sensing ic enabling 0 5 mm diameter stylus signal detection at 240 hz reporting rate with palm rejection
Asian Solid-State Circuits Conference, 2014Co-Authors: Shinichi Yoshida, Mutsumi Hamaguchi, Akira Nagao, Takahiro Morishita, Shinji Shinjo, Masayuki MiyamotoAbstract:A touch sensing system capable of stylus input should have “palm rejection” function which allows the user to place one's palm on the surface of the touch sensor while writing with a stylus. In order to realize “palm rejection”, it is necessary to detect the small stylus while neglecting large signal from the palm. However this is not sufficient because small electrical noise injected through the palm into the touch sensor impedes stylus input signal in real use. This issue is because the injected noise propagates onto the touch sensor's sense channels which are capacitively-coupled with the palm and degrades the SNR of the stylus signal on the channels. A simple and effective technique to eliminate this issue is implemented in a newly developed 87×49 Mutual Capacitance touch sensing IC which is fabricated in an 85 nm CMOS technology. It achieves an SNR over 33 dB for a 0.5 mm-diameter stylus when a 10 Vp-p sinusoidal noise is injected to the stylus and the palm. Both the die area and the power consumption of a unit charge-to-voltage converter (CVC) designed for the IC are reduced to approximately 50% compared to those of the previous implementation [4]. In order not to report unwanted touches due to palm signals, a palm detection filter is implemented in the digital signal processor on the IC.
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12 3 a 240hz reporting rate 143 81 Mutual Capacitance touch sensing analog front end ic with 37db snr for 1mm diameter stylus
International Solid-State Circuits Conference, 2014Co-Authors: Mutsumi Hamaguchi, Akira Nagao, Masayuki MiyamotoAbstract:Realization of a Mutual-Capacitance touch-sensing system spanning over 30 inches is not a straightforward task, because the SNRs of conventional sequential drive controllers degrade as the number of sensor channels increases. One common way to overcome this drawback is to increase the driving voltage, which however results in an increase in system complexity and cost because it requires high-voltage circuits and devices. This SNR issue is resolved by driving the sensor channels in parallel [1,4] as shown in Fig. 12.3.1. Although the parallel drive mixes up the signals from the multiple channels driven at the same time, the original signals can be reconstructed from the sequence of mixed signals if the drive sequences are linearly independent from each other. By appropriately designing the parallel drive sequences, the SNR is enhanced by √M times compared to that of the sequential drive [1], where M is the number of drive channels. An analog front-end (AFE) IC capable of driving and sensing a 143×81 Mutual-Capacitance sensor is developed in 0.18μm 1P5M CMOS. A 32-inch and a 70-inch touch system are realized with the use of the AFE and an SNR over 37dB for 1mm diameter stylus is attained in either system.
Deogkyoon Jeong - One of the best experts on this subject based on the ideXlab platform.
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a Mutual Capacitance touch readout ic with 64 reduced power adiabatic driving over heavily coupled touch screen
IEEE Journal of Solid-state Circuits, 2019Co-Authors: Jiheon Park, Youngha Hwang, Yoonho Song, Juneun Park, Deogkyoon JeongAbstract:This paper presents a touch sensing analog front end (AFE) for capacitive touch-screen integrated into an ultra-thin display. Reduced distance between the touch screen and display causes large capacitive coupling, resulting in increased parasitic Capacitance and reduced touch sensitivity. Display noise interference is worse due to the large coupling Capacitance. Hence, it is a challenge to design an AFE capable of accurate and energy efficient sensing of a touch input in the integrated touch-screen panel. An adiabatic multi-driving method based on charge recycling is proposed to provide power-efficient stimulation of the touch-screen panel. Furthermore, in order to cancel out the display noise interference through the large parasitic Capacitance, a fully differential touch sensing module is incorporated in the AFE. A correlated noise sampling (NS) is employed in the decoder stage for the multi-driving demodulation process. To further improve power efficiency, the sensing module is multiplexed in four ways while achieving an optimal conversion time per sample. The proposed AFE was implemented in a 180-nm CMOS process. The fabricated AFE shows 57.0-dB signal-to-noise ratio (SNR) at 120 fps while consuming 17.8 mW. Compared with power consumption of 19.9 mW expected with a conventional signal generation, the proposed adiabatic signal generator dissipates only 7.1 mW, exhibiting a power reduction of 64% due to the adiabatic driving method.
Hideki Asai - One of the best experts on this subject based on the ideXlab platform.
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block latency insertion method block lim for fast transient simulation of tightly coupled transmission lines
IEEE Transactions on Electromagnetic Compatibility, 2011Co-Authors: Tadatoshi Sekine, Hideki AsaiAbstract:This paper describes a block-latency insertion method (LIM) for the fast transient simulation of the large networks with many coupling elements. First, the basic formulation of LIM is reviewed. Next, the block-LIM formulation for the network with many coupling elements, such as the Mutual inductance, the Mutual Capacitance, and controlled sources is described. Then, the block-LIM algorithm is applied to the tightly coupled transmission lines, which are connected to each other by a number of Mutual inductors and capacitors. Finally, some numerical results are shown, and it is confirmed that the proposed technique is useful and efficient for the simulation of the tightly coupled transmission lines.
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block latency insertion method block lim for fast transient simulation of tightly coupled transmission lines
International Symposium on Electromagnetic Compatibility, 2009Co-Authors: Tadatoshi Sekine, Hideki AsaiAbstract:This paper describes a block matrix formulation of latency insertion method (LIM) for the fast transient simulation of the circuit which includes the elements such as Mutual inductance and Mutual Capacitance. First, the basic formulation of LIM is shown. Next, the block-LIM formulation for the network with Mutual inductance and Mutual Capacitance is described. Then, the block-LIM algorithm is applied to the tightly coupled transmission lines which are connected each other by a number of Mutual inductors and capacitors. Finally, some numerical results are shown and it is confirmed that the proposed technique is useful and efficient for the simulations of the tightly coupled transmission lines.
