Pulse-width-independent low power programmable low temperature poly-Si thin-film transistor shift register

Song, Eun-Ji; Song, Seok-Jeong; Nam, Hyoungsik

doi:10.1016/j.sse.2014.12.026

Cited by 11 publications

(8 citation statements)

References 10 publications

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“…. Threshold voltage, mobility, and overlap capacitance are 1.94 V, 37.907 cm 2 /V∙s and 0.16 fF/μm, respectively …”

Section: Simulation Results and Discussionmentioning

confidence: 99%

“…To cope with this crosstalk artifact while increasing the touch reporting rate, an in‐cell touch panel conducts touch sensing and displays scanning operations separately based on a time division driving method (TDDM) . In addition, the overall cost of display manufacturing is further reduced by implementing gate driver circuits with thin film transistors (TFTs) on a panel . In the TDDM, the display area is divided into several blocks in between which touches are detected.…”

Section: Introductionmentioning

confidence: 99%

“…6 In addition, the overall cost of display manufacturing is further reduced by implementing gate driver circuits with thin film transistors (TFTs) on a panel. [7][8][9][10][11][12][13][14] In the TDDM, the display area is divided into several blocks in between which touches are detected. That is, the touch sensing starts after completing the scanning of a certain display block and the next block scanning continues after the touch sensing is carried out.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Robust integrated shift register circuit over clock noises for in‐cell touch applications

Seo

Nam

2017

J Soc Info Display

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This paper proposes an integrated shift register circuit for an in‐cell touch panel that is robust over clock noises. It is composed of 10 thin film transistors and 1 capacitor, and the time division driving method is adopted to prevent the negative effect of display signals on the touch sensing. Two pre‐charging nodes are employed for reducing the uniformity degradation of gate pulses over time. In particular, the proposed circuit connects a drain of the first pre‐charging node's pull‐up thin film transistor (TFT) to the positive supply voltage instead of clock signals. This facilitates to lower coupling noises as well as to clock power consumption. The simulation program with an integrated circuit emphasis is conducted for the proposed circuit with low temperature poly‐silicon TFTs. The positive threshold voltage that shifts up to 12 V at the first pre‐charging pull‐up TFT can be compensated for without the uniformity degradation of gate pulses. For a 60‐Hz full‐HD display with a 120‐Hz reporting rate of touches, the clock power consumption of the proposed gate driver circuit is estimated as 7.13 mW with 160 stages of shift registers. In addition, the noise level at the first pre‐charging node is lowered to −28.95 dB compared with 2.37 dB of the previous circuit.

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“…. Threshold voltage, mobility, and overlap capacitance are 1.94 V, 37.907 cm 2 /V∙s and 0.16 fF/μm, respectively …”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Robust integrated shift register circuit over clock noises for in‐cell touch applications

Seo

Nam

2017

J Soc Info Display

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“…The control signal of EM connected to a p-channel TFT (T4) is applied at the high voltage level to make the drain of T1 floating and to keep the OLED from emitting the undesired light during both V th detecting and data writing periods. These EM pulses, which are wider than gate pulses, have been generated by additional shift registers with wide clock pulses or programmable pulse width shift registers [28][29][30]. While previous circuits maintain the pulse width of EM signals to be equivalent for all pixels, EM pulse widths for these foveation-based driving pixels should be adjusted differently depending on the resolution of the driven panel area.…”

Section: Em Signal Generation For Oled Pixelsmentioning

confidence: 99%

Variable Clock and EM Signal Generation Scheme for Foveation-Based Driving OLED Head-Mounted Displays

2021

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An image processing pipeline and multi-output shift register of a foveation-based driving scheme are proposed for the realization of immersive head-mounted displays in 2019. In addition, this paper describes a variable clock generation circuit to manipulate output waveforms of shift registers in the foveated display. The EM circuit for OLED displays is also introduced to support the control signal to keep OLEDs of pixels from emitting light during the compensation. Especially, the EM circuit consists of only four TFTs and one capacitor and gives rise to pulses of variable widths corresponding to the resolution of a driven display area. A variable clock generation scheme is verified with 60 Hz 1440 × 2560 monitor, eye-tracker, PSoC board and FPGA board. An EM circuit is simulated by SPICE for 9600 lines and 120 Hz foveated displays.

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“…The previous EM circuits have programed the duty ratio by changing the start pulsewidth applied to the first stage and shifted the pulse in a fashion of stage-by-stage by means of the same clock signals used in scanning shift registers [13], [18], [19], [20]. However, their pulsewidth tunability is limited by odd or even number multiples of the line time.…”

Section: Introductionmentioning

confidence: 99%

Fine-Tunable Emission Pulse Generation Circuit Based on p-Type Low-Temperature Poly-Si Thin-Film Transistors for Active Matrix Organic Light-Emitting Diode Displays

Chang

Kim

Nam

2023

IEEE Trans. Electron Devices

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Active matrix organic light-emitting diode (AMOLED) displays have deployed the compensation techniques to cope with the luminance non-uniformity issues caused by variations on electrical characteristics of thin-film transistors (TFTs). While some compensation circuits require control signals of longer pulse widths than a line time, the luminance control as well as the higher bit depth representation have been also accomplished by adjusting the pulse widths. A proposed EM pulse generation circuit consists of 11 p-type low-temperature poly-Si (LTPS) TFTs and a one coupling capacitor. While previous tunable circuits could address pulse widths of either even or odd multiples of a line time, the proposed circuit can generate any multiples by changing phases of additional clock signals. In particular, the internal inverter is implemented with a load connected to the output of a previous stage's inverter to reduce the power consumption over pulse widths. The coupling capacitor is also connected between two adjacent stages through one TFT, eliminating coupling noises on the output pulses. The proposed EM circuit is simulated at a line time of 3.8 µs for a 120 Hz 3840 × 2160 display. The results ensure that pulse widths from three to 2160 lines are generated successfully without coupling noises and the small variation on power consumption from 1.23 to 0.33 mW is achieved at 30 stages for the whole range of pulse widths, compared to the large range from 1.26 to 76.91 mW with the inverter of a diodeconnected load.

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Pulse-width-independent low power programmable low temperature poly-Si thin-film transistor shift register

Cited by 11 publications

References 10 publications

Robust integrated shift register circuit over clock noises for in‐cell touch applications

Robust integrated shift register circuit over clock noises for in‐cell touch applications

Variable Clock and EM Signal Generation Scheme for Foveation-Based Driving OLED Head-Mounted Displays

Fine-Tunable Emission Pulse Generation Circuit Based on p-Type Low-Temperature Poly-Si Thin-Film Transistors for Active Matrix Organic Light-Emitting Diode Displays

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