Tzu-Ming Wang

Design on mixed-voltage I/O buffers with slew-rate control in low-voltage CMOS process

A new design on mixed-voltage I/O buffers with slew-rate control but without gate-oxide reliability problem in low-voltage CMOS process is proposed. The proposed circuit can effectively reduce the ground bounce effects without suffering gate-oxide reliability problems and hot-carrier degradation issues. The proposed mixed-voltage I/O buffer with slew-rate control has been designed in a 0.18-mum CMOS process to meet the 1.5-V/3.3-V applications.

Design of Mixed-Voltage-Tolerant Crystal Oscillator Circuit in Low-Voltage CMOS Technology

In the nanometer-scale CMOS technology, the gate-oxide thickness has been scaled down to provide higher operating speed with lower power supply voltage. However, regarding compatibility with the earlier defined standards or interface protocols of CMOS ICs in a microelectronics system, the chips fabricated in the advanced CMOS processes face the gate-oxide reliability problems in the interface circuits due to the voltage levels higher than normal supply voltage (1× VDD) required by earlier applications. As a result, mixed-voltage I/O circuits realized with only thin-oxide devices had been designed with advantages of less fabrication cost and higher operating speed to communicate with the circuits at different voltage levels. In this paper, two new mixed-voltage-tolerant crystal oscillator circuits realized with low-voltage CMOS devices are proposed without suffering the gate-oxide reliability issues. The proposed mixed-voltage crystal oscillator circuits, which are one of the key I/O cells in a cell library, have been designed and verified in a 90-nm 1-V CMOS process, to serve 1-V/2-V tolerant mixed-voltage interface applications.

Design and Implementation of Readout Circuit on Glass Substrate for Touch Panel Applications

A readout circuit on glass substrate for touch panel application has been designed and fabricated in a 3- low temperature poly-silicon (LTPS) technology. In this work, the switch-capacitor (SC) technique is applied to amplify the small voltage difference from capacitance change due to the touch event on panel. In addition, the corrected double-sampling (CDS) technique is also employed to reduce the offset originated from LTPS process variation. The minimum detectable voltage difference of the proposed circuit is 40 mV. To further identify the different touch area during touch events, a 4-bit analog-to-digital converter is used to converter the output of readout circuit into 4-bit digital codes.

P-178: Design of On-Panel Readout Circuit for Touch Panel Application

An on-panel readout circuit for touch panel application has been designed and fabricated in a 3-μm low temperature poly-silicon (LTPS) technology. The minimum detectable voltage difference of the proposed circuit is 30 mV. The switch-capacitor technique is applied to amplify the voltage difference from capacitance change due to touch panel. The corrected double-sampling (CDS) technique is also employed to reduce the offset originated from process variation.

Design and implementation of capacitive sensor readout circuit on glass substrate for touch panel applications

A capacitive sensor readout circuit on glass substrate for touch panel applications has been designed and fabricated in a 3-μm low temperature poly-silicon (LTPS) technology. In this work, the small voltage difference from capacitance change due to the touch event on panel is amplified by the switch-capacitor (SC) technique. In order to reduce the effect from device characteristic variation in LTPS process, the proposed readout circuit applies the corrected double-sampling (CDS) technique to reduce the offset originated from LTPS process variation. To enhance the resolution of touch panel, a 4-bit analog-to-digital converter is utilized to identify the different touch area conditions.

On-glass digital-to-analog converter with gamma correction for panel data driver

An on-glass 6-bit R-string digital-to-analog converter (DAC) with gamma correction for panel data driver is proposed. The proposed circuit, which is composed of folded R-string circuit, segmented digital decoder, and reordering decoding circuit, has been designed and fabricated in a 3-mum low-temperature poly-Si (LTPS) technology. The area of the proposed circuit is effectively reduced to about one sixth compared with the conventional one.

P-49: Design of Digital Time-Modulation Pixel Memory Circuit on Glass Substrate for Low Power Application

A digital time-modulation pixel memory circuit on glass substrate has been designed and verified in a 3-μm low temperature poly-silicon (LTPS) technology. The proposed circuit can generate 4-bit digital codes and the corresponding inversion data by time-modulation technique to refresh the static image without activating the data driver circuit. Therefore, the data driver of liquid crystal display (LCD) panel is not required to provide the image data of the frame by the proposed circuit while the LCD panel operates in the still mode. The power consumption from data driver can be further reduced in the LCD panel.

Digital time-modulation pixel memory circuit in LTPS technology

— A digital time-modulation pixel memory circuit on glass substrate has been designed and verified for a 3-μm low-temperature polysilicon (LTPS) technology. From the experimental results, the proposed circuit can generate 4-bit digital codes and the corresponding inversion data with a time-modulation technique. While the liquid-crystal-display (LCD) panel operates in the still mode, which means the same image is displayed on the panel, a data driver for an LCD panel is not required to provide the image data of the frame by the proposed pixel memory circuit. This pixel memory circuit can store the frame data and generate its corresponding inversion data to refresh a static image without activating the data driver circuit. Therefore, the power consumption of a data driver can be reduced in the LCD panel.

Digital-to-analog converter with gamma correction on glass substrate for TFT-panel applications

Low-temperature polysilicon (LTPS) technology has a tendency towards integrating all circuits on glass substrate. However, the poly-Si TFTs suffered poor uniformity with large variations in the device characteristics due to a narrow laser process window for producing large-grained poly-Si TFTs. The device variation is a serious problem for circuit realization on the LCD panel, so how to design reliable on-panel circuits is a challenge for system-on-panel (SOP) applications. In this work, a 6-bit R-string digital-to-analog converter (DAC) with gamma correction on glass substrate for TFT- panel applications is proposed. The proposed circuit, which is composed of a folded R-string circuit, a segmented digital decoder, and reordering of the decoding circuit, has been designed and fabricated in a 3-µm LTPS technology. The area of the new proposed DAC circuit is effectively reduced to about one-sixth compared to that of the conventional circuit for the same LTPS process.

2xVDD-tolerant crystal oscillator circuit realized with 1xVDD CMOS devices without gate-oxide reliability issue

A new 2xVDD-tolerant crystal oscillator circuit realized with 1xVDD CMOS devices without suffering gate-oxide reliability issue is proposed, which is one of the key mixed- voltage I/O cells in a cell library. The proposed circuit is realized with only thin gate-oxide devices with floating n-well technique. The proposed 2xVDD-tolerant crystal oscillator circuit has been designed and verified in a 90-nm 1-V CMOS process to serve 1/2-V mixed-voltage interface applications.