Highly Robust Integrated Gate-Driver for In-Cell Touch TFT-LCD Driven in Time Division Driving Method

Moon, Suhwan; Haruhisa, Iida; Kim, Kwan; Park, Chulwoo; Chung, Hongsuk; Kim, Sung Hoon; Kim, Byeong‐Koo; Kim, Ohyun

doi:10.1109/jdt.2015.2495121

Cited by 21 publications

(19 citation statements)

References 14 publications

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“…For a TDDM, one frame period is divided into 12 display blocks and 12 touch sensing periods are inserted between display blocks as shown in Fig. . The line time and frame time are 4 μs and 16 ms for a 60‐Hz full‐HD (1920 × 1080) display with a 120‐Hz touch reporting rate.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

“…6. 15 The line time and frame time are 4 μs and 16 ms for a 60-Hz full-HD (1920 × 1080) display with a 120-Hz touch reporting rate. The time duration of display block and touch sensing period is 690 μs that includes 160 display lines.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

“…Figures 7 and 8 show simulated waveforms for the 16th stage of a normal scanning period and the 161st stage of a touch sensing period. For the 16th stage, the previous output V g [15] charges A [16] up, which drives Q [16] up to a high voltage. Then, when CLK is asserted, A [16] is discharged to VGL and Q [16] is bootstrapped up to 40 V by CLK to pull V g [16] FIGURE 5 -Configuration of shift registers for simulation.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

“…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 . Therefore, the gate driver circuit should be able to stop at a certain line and restart from that line.…”

Section: Introductionmentioning

confidence: 99%

“…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. 15 Therefore, the gate driver circuit should be able to stop at a certain line and restart from that line. It requires a shift register to maintain the high voltage for a longer period than other ones, which causes the uniformity degradation of gate pulses leading to the visible line artifacts between display blocks due to the threshold voltage (Vth) shift of pullup TFTs.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Simulation Results and Discussionmentioning

confidence: 99%

Section: Simulation Results and Discussionmentioning

confidence: 99%

Section: Simulation Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 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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Active in‐cell touch circuit using floating common electrode as sensing pad for the large size in‐plane‐switching liquid crystal displays

2017

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In this paper, we propose an in-cell active touch circuit using the concept of floating common electrode for large size in-plane-switching liquid crystal displays. Compared with the conventional passive in-cell touch circuit, the proposed method can greatly reduce the readout channel numbers by sharing the sensing bus for one column. Because the touch signal is amplified in the pixel, the touch panel can be easily scaled up in size. Simulation results show that the difference between touch and no-touch signals can be as large as 10 μA even with threshold voltage shift of ±1 V. The possible issues of the proposed method are experimentally verified.

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A compact gate driver with bifunctional capacitor for in‐cell touch mobile display

et al. 2021

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A thin‐film transistors (TFTs) integrated gate driver circuit with bifunctional capacitors for in‐cell touch with horizontal blanking display mode is proposed in this paper. The coupling capacitor, which conventionally enables low‐level‐maintaining parts in display periods, is reused to store transfer charges during touch detection periods. Consequently, only nine TFTs and two capacitors are used for a single stage of the proposed gate driver for in‐cell touch display. Furthermore, the bifunctional capacitor scheme not only avoids the driving TFT from long‐time voltage stress but also suppresses the transfer charges leakage effectively. Therefore, the variation ratios of rising/falling time between adjacent gate driver stages are suppressed within 6%. For a 5.7‐in. display with HD+ resolution, the layout of a single gate driver stage is 623 μm (width) × 171 μm (height). The proposed gate driver circuit has been prepared with the state‐of‐the‐art hydrogenated amorphous silicon (a‐Si:H) TFT manufacturing process. The measured results verified the circuit functions. The gate driver output waveforms are well maintained and being almost independent of touch detection time interval from 100 to 300 μs.

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Highly Robust Integrated Gate-Driver for In-Cell Touch TFT-LCD Driven in Time Division Driving Method

Cited by 21 publications

References 14 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

Active in‐cell touch circuit using floating common electrode as sensing pad for the large size in‐plane‐switching liquid crystal displays

A compact gate driver with bifunctional capacitor for in‐cell touch mobile display

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