Analog PWM Method with Sweep Generation Structure Based on P-Type LTPS TFTs for Micro-LED Displays

Chih Lung Lin; Cheng Han Ke; Jui Hung Chang; Chieh An Lin; Chia En Wu; Ming Hsien Lee

doi:10.1109/JEDS.2023.3324065

Analog PWM Method with Sweep Generation Structure Based on P-Type LTPS TFTs for Micro-LED Displays

Chih Lung Lin, Cheng Han Ke, Jui Hung Chang, Chieh An Lin, Chia En Wu, Ming Hsien Lee

Department of Electrical Engineering

Research output: Contribution to journal › Article › peer-review

6 Citations (Scopus)

Abstract

This work proposes a novel pixel circuit using analog pulse width modulation (PWM) for micro light-emitting diode (micro-LED) displays. The proposed circuit generates uniform sweep waveforms and driving currents to control micro-LED emission precisely by compensating for threshold voltage (VTH) variations of p-type low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) and VDD current-resistance drops (I-R drops). Driven by the PWM method, micro-LED can operate with high wall-plug efficiency (WPE), leading to low power consumption. To analyze the circuit performance, the electrical characteristics of a micro-LED and LTPS TFTs are measured to establish the simulated models. The HSPICE simulation results present that the current error rates and time shift rates of emission currents are below 1.65% and 2.75%, respectively, with ±0.3 V variations in VTH and 1.2 V drops in VDD. Furthermore, the power improvement relative to a 7T1C pulse amplitude modulation (PAM) circuit is higher than 19.05% at all gray levels, confirming that the proposed circuit is suitable for use in micro-LED displays.

Original language	English
Pages (from-to)	573-578
Number of pages	6
Journal	IEEE Journal of the Electron Devices Society
Volume	11
DOIs	https://doi.org/10.1109/JEDS.2023.3324065
Publication status	Published - 2023

All Science Journal Classification (ASJC) codes

Biotechnology
Electronic, Optical and Magnetic Materials
Electrical and Electronic Engineering

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10.1109/JEDS.2023.3324065

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@article{daf1b1ee64654e3baf6afe0219a63c3f,

title = "Analog PWM Method with Sweep Generation Structure Based on P-Type LTPS TFTs for Micro-LED Displays",

abstract = "This work proposes a novel pixel circuit using analog pulse width modulation (PWM) for micro light-emitting diode (micro-LED) displays. The proposed circuit generates uniform sweep waveforms and driving currents to control micro-LED emission precisely by compensating for threshold voltage (VTH) variations of p-type low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) and VDD current-resistance drops (I-R drops). Driven by the PWM method, micro-LED can operate with high wall-plug efficiency (WPE), leading to low power consumption. To analyze the circuit performance, the electrical characteristics of a micro-LED and LTPS TFTs are measured to establish the simulated models. The HSPICE simulation results present that the current error rates and time shift rates of emission currents are below 1.65% and 2.75%, respectively, with ±0.3 V variations in VTH and 1.2 V drops in VDD. Furthermore, the power improvement relative to a 7T1C pulse amplitude modulation (PAM) circuit is higher than 19.05% at all gray levels, confirming that the proposed circuit is suitable for use in micro-LED displays.",

author = "Lin, {Chih Lung} and Ke, {Cheng Han} and Chang, {Jui Hung} and Lin, {Chieh An} and Wu, {Chia En} and Lee, {Ming Hsien}",

note = "Publisher Copyright: {\textcopyright} 2013 IEEE.",

year = "2023",

doi = "10.1109/JEDS.2023.3324065",

language = "English",

volume = "11",

pages = "573--578",

journal = "IEEE Journal of the Electron Devices Society",

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T1 - Analog PWM Method with Sweep Generation Structure Based on P-Type LTPS TFTs for Micro-LED Displays

AU - Lin, Chih Lung

AU - Ke, Cheng Han

AU - Chang, Jui Hung

AU - Lin, Chieh An

AU - Wu, Chia En

AU - Lee, Ming Hsien

PY - 2023

Y1 - 2023

N2 - This work proposes a novel pixel circuit using analog pulse width modulation (PWM) for micro light-emitting diode (micro-LED) displays. The proposed circuit generates uniform sweep waveforms and driving currents to control micro-LED emission precisely by compensating for threshold voltage (VTH) variations of p-type low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) and VDD current-resistance drops (I-R drops). Driven by the PWM method, micro-LED can operate with high wall-plug efficiency (WPE), leading to low power consumption. To analyze the circuit performance, the electrical characteristics of a micro-LED and LTPS TFTs are measured to establish the simulated models. The HSPICE simulation results present that the current error rates and time shift rates of emission currents are below 1.65% and 2.75%, respectively, with ±0.3 V variations in VTH and 1.2 V drops in VDD. Furthermore, the power improvement relative to a 7T1C pulse amplitude modulation (PAM) circuit is higher than 19.05% at all gray levels, confirming that the proposed circuit is suitable for use in micro-LED displays.

AB - This work proposes a novel pixel circuit using analog pulse width modulation (PWM) for micro light-emitting diode (micro-LED) displays. The proposed circuit generates uniform sweep waveforms and driving currents to control micro-LED emission precisely by compensating for threshold voltage (VTH) variations of p-type low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) and VDD current-resistance drops (I-R drops). Driven by the PWM method, micro-LED can operate with high wall-plug efficiency (WPE), leading to low power consumption. To analyze the circuit performance, the electrical characteristics of a micro-LED and LTPS TFTs are measured to establish the simulated models. The HSPICE simulation results present that the current error rates and time shift rates of emission currents are below 1.65% and 2.75%, respectively, with ±0.3 V variations in VTH and 1.2 V drops in VDD. Furthermore, the power improvement relative to a 7T1C pulse amplitude modulation (PAM) circuit is higher than 19.05% at all gray levels, confirming that the proposed circuit is suitable for use in micro-LED displays.

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Analog PWM Method with Sweep Generation Structure Based on P-Type LTPS TFTs for Micro-LED Displays

Abstract

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