• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.197-200
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• 2008

We propose a novel n-type a-Si:H TFT pixel circuit which is proper to AMOLED display for the large size and high resolution. Proposed pixel circuit will be suit to panel for the high resolution because of different threshold sampling method. Driving method of proposed pixel circuit is very simple like an AMLCD. Our simulation indicates that the proposed pixel circuit can compensate the Vth shift and IR rising of power line so that provide better quality image.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.257-260
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• 2002

This paper describes the pixel of AMOLED(act ive matrix organic light emitting diode) driving circuit by poly-sl technology. The area per pixel is 278um$\times$278um in 120$\times$160(2.2 inch) Driving the OLEDS with active matrix leads to the lower voltage operation, the lower peak pixel currents and the display with much greater efficiency and brightness The role of the active matrix is to provide a constant current throughout the entire frame time and is eliminating the high currents encountered In the passive matrix approach, This design can support the high resolutions expected by the consumer because the current variation specification is norestricted. The pixel has been designed driving TFT threshold voltage cancellation circuit and wide aperture ratio circuit that communizes 4 pixel. The test simulation results and layout are 11% per threshold-current var Eat ion and 12.5% the aperture ratio of increase.

• Journal of IKEEE
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• v.19 no.1
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• pp.1-9
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• 2015

This paper proposes the design of sub-pixel interpolation circuit for real-time multi-decoder supporting 4K-UHD video images. The proposed sub-pixel interpolation circuit supports H.264, MPEG-4, VC-1 and new video compression standard HEVC. The common part of the interpolation algorithm used in each video compression standard is shared to reduce the circuit size. An intermediate buffer is effectively used to reduce the circuit size and optimize the performance. The proposed sub-pixel interpolation circuit was synthesised by using 130nm standard cell library. The synthesized gate-level circuit consists of 122,564 gates and processes 35~86 image frames per second for 4K-UHD video at the maximum operation frequency of 200MHz. Therefore, the proposed circuit can process 4K-UHD video in real time.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.1-5
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• 2009

A new pixel circuit for Active Matrix Organic Light Emitting Diodes (AMOLEDs), based on the polycrystalline silicon thin film transistors (Poly-Si TFTs), was proposed and verified by SMART SPICE simulation. One driving and six switching TFTs and one storage capacitor were used to improve display image uniformity without any additional control signal line. The proposed pixel circuit compensates an inevitable threshold voltage variation of Poly-Si TFTs and also compensates the degradation of OLED at low power supply voltage($V_{DD}$). The simulation results show that the proposed pixel circuit successfully compensates the variation of OLED driving current within 0.8% compared with 20% of the conventional pixel circuit.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.3
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• pp.279-284
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• 2014

This paper proposes a novel OLED pixel circuit to compensate the threshold voltage variation of p-channel low temperature polycrystalline silicon thin-film transistors (LTPS TFTs). The proposed 5-TFT OLED pixel circuit consists of 4 switching TFTs, 1 OLED driving TFT and 1 capacitor. One frame of the proposed pixel circuit is divided into initialization period, threshold voltage sensing and data programming period, data holding period and emission period. SmartSpice simulation results show that the maximum error rate of OLED current is -4.06% when the threshold voltage of driving TFT varies by ${\pm}0.25V$ and that of OLED current is 9.74% when the threshold voltage of driving TFT varies by ${\pm}0.50V$. Thus, the proposed 5T1C pixel circuit can realize uniform OLED current with high immunity to the threshold voltage variation of p-channel poly-Si TFT.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1297-1303
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• 2003

This paper propose an advanced circuit for fingerprint sensor signal processing. We increased the voltage between ridge and valley by modifying the parasitic capacitance eliminating circuit of sensor plate. The analog comparator was designed for comparing the sensor signal voltage with the reference signal voltage. We also propose an effective isolation strategy for removing noise and signal coupling, ESD of each sensor pixel. The 128${\times}$l44 pixel fingerprint sensor circuit was designed and simulated, and the layout was performed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.531-536
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• 2009

In this paper, we propose $256{\times}256$ pixel array fingerprint sensor with an advanced circuits for detecting. The pixel level simple detection circuit converts from a small and variable sensing current to binary voltage out effectively. We minimizes an electrostatic discharge(ESD) influence by applying an effective isolation structure around the unit pixel. The sensor circuit blocks were designed and simulated in standard CMOS $0.35{\mu}m$ process. Full custom layout is performed in the unit sensor pixel and auto placement and routing is performed in the full chip.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.22-23
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• 2006

A new current-driving pixel circuit for active-matrix organic light-emitting diodes (AMOLEDs), composed of four organic thin-film transistors (OTFTs) and one capacitor, is proposed using a current scaling method. Designing pixel circuits with OTFTs has many problems due to the instability of the OTFT parameters with still unknown characteristics of the material. Despite the problems in using OTFTs to drive the pixel circuit, our work could be set as a goal for future OTFT development. The simulation results show enhanced linearity between input data and OLEO luminescence at low current levels as well as successfully compensating the variation of the OTFTs, such as the threshold voltage and mobility.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.335-336
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• 2007

A new current-programmed pixel circuit for activematrix organic light emitting diodes (AMOLEDs), based on Organic TFTs (OTFTs), is proposed and verified by SPICE simulations. The simulation results show that the proposed pixel circuit, which is a current mirror structure consisting of five Organic TFTs and one capacitor, has reliable linear characteristics between input current and output OLED current. Also, the threshold voltage degradation of Organic TFTs due to long time operation stress is well compensated to reliable values.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.141-145
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• 2021

The brightness of the Organic Light Emitting Diode (OLED) display is controlled by thin-film transistors (TFTs). Regardless of the materials and the structures of TFTs, an OLED suffers from the instable threshold voltage (V_th) of a TFT during operation. When designing an OLED pixel with circuit simulation tool such as SPICE, a designer needs to take V_th shift into account to improve the reliability of the circuit and various compensation methods have been proposed. In this paper, the effect of the compensation circuits from two typical OLED pixel circuits proposed in the literature are studied by the transient simulation with a SPICE tool in which the stretched-exponential time dependent V_th shift function is implemented. The simulation results show that the compensation circuits improve the reliability at the beginning of each frame, but V_th shifts from all TFTs in a pixel need to be considered to improve long-time reliability.