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Design of Pixel Circuit Using a-IGZO TFTs to Enhance Uniformity of AMOLED Displays by Threshold Voltage Compensation

  • Research Article-Electrical Engineering
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Abstract

This article presents a novel voltage-programmed pixel circuit using a-IGZO TFTs to effectively compensate threshold voltage (VTH) variations of driving TFT. The compensation is very important to maintain the pixel brightness of active-matrix organic light-emitting diodes (AMOLED) displays. The proposed pixel design uses four-phase clocking schemes: reset period, VTH detection period, data input period and emission period. To maintain uniformity in phases, the duration of all the phases is taken to be same which results in easier design of the multi-phase clock. Moreover, the switching speed of control signals is as high as 25 kHz, ensuring a high frame rate. The circuit has been simulated extensively, and the operation has been verified using SPICE models of a-IGZO TFT and OLED on Cadence Spectre. The circuit also achieves high contrast as OLED does not emit light in any periods except the emission period. The OLED current error in the proposed design for a VTH variation of 170% is below 0.1%. This circuit also provides a high aperture ratio of 51.6%, which ensures high resolution of AMOLED displays.

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Authors and Affiliations

  1. Department of Electrical and Electronics Engineering, Birla Institute of Technology and Science Pilani, Pilani, Rajasthan, India

    Aditya Sodhani

  2. Department of Electronics and Communication Engineering, Tezpur University, Tezpur, Assam, India

    Rupam Goswami

  3. Department of Electronics and Communication Engineering, Indian Institute of Information Technology Allahabad, Prayagraj, U.P., India

    Kavindra Kandpal

Authors
  1. Aditya Sodhani
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  2. Rupam Goswami
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  3. Kavindra Kandpal
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Correspondence to Kavindra Kandpal.

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Sodhani, A., Goswami, R. & Kandpal, K. Design of Pixel Circuit Using a-IGZO TFTs to Enhance Uniformity of AMOLED Displays by Threshold Voltage Compensation. Arab J Sci Eng 46, 9663–9672 (2021). https://doi.org/10.1007/s13369-021-05457-2

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  • DOI: https://doi.org/10.1007/s13369-021-05457-2

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