Display Driver Circuit Research Articles

High Performance Amorphous IGO Thin Film Transistors Grown at Low Temperature

Polycrystalline indium gallium oxide has been widely studied in the domain of oxide thin film transistors (TFTs) due to its high mobility. However, there are few researches focus on amorphous IGO (a‐IGO), which has the advantage of large area display. Herein, high‐performance a‐IGO TFTs are demonstrated by magnetron sputtering method with simple process. The efficiency of a‐IGO TFTs fabricated under various conditions are evaluated, and a‐IGO TFTs prepared by 27 nm thin films grown at 220 °C have the best electrical properties. It exhibits the mobility of 35 cm2 V−1 s−1, threshold voltage of 0.5 V, subthreshold swing of 0.8 V dec−1, and the on/off current ratio over 106. This is due to the precise control of the deposition energy state by temperature during sputtering and the influence of the semiconductor layer thickness on the distribution of the accumulation layer. The results present here demonstrate a simple fabrication method for high‐performance amorphous oxide TFT, providing a new option for display driver circuits.

4‐4: High PPI MicroLED display driver circuit and device structure

This paper proposes a new type of display driver circuit and TFT device structure, studies the brightness control technology of high PPI Micro LED display, uses the inverter PWM driver module loaded in the traditional internal compensation driver circuit, when the low gray scale display, By triggering PWM module, the PWM is used to further divide the low gray scale under PAM mode again, so as to increase the gray level. Meanwhile, the introduction of Micro LED reverse NMOS and PMOS laminator TFT increases the PPI from 233 to 314 retinal level. Realized the Micro LED HD display and low brightness controllable demand.

P‐10.5: Design and Comparison of DRAM and SRAM Micro‐LED Pixel Driver Circuits

With the human stepping into the information society and the rapid increase of information, various display facilities and display devices are getting unprecedented development. In the display industry, Micro-LED has become the focus of development because it has the advantages of both traditional LED and small size, and can achieve extremely high PPI. However, it is precisely because of its small size, in order to drive Micro-LED display, it is particularly important to design a separate driver circuit that meets its characteristics. In this paper, different structures of pixel drivers in Micro-LED display driver circuits are studied. By comparing DRAM and SRAM structures, the performance of pixel driver under different frequency conditions is analyzed. This paper introduces and analyzes the circuit structure and design flow of various pixel drivers. Simulation is carried out by Cadence software, and its actual performance is verified by taping out.

Achieving Matrix Quantum Dot Light-Emitting Display Based on All-Inorganic CsPbBr₃ Perovskite Nanocrystal Composites

We present a display consisting of a 64-cell quantum dot (QD) light-emitting diodes (LEDs) array manufactured by spin coating and steel plate design evaporation technology. The QDLED pixels in the array can be driven independently. The surface of perovskite nanocrystal (NC) composite was modified by using pure natural material aloe-vera gel as the organic precursor to obtain high-quality narrow band photoluminescence emission all-inorganic CsPbBr3 perovskite NC composites. Here, an open-source Arduino microcontroller unit was used as the dynamic micro-control terminal, combined with a step-down module and four motor drive modules to make the display driver circuit. Finally, a 99% operating rate and a maximum brightness of 3366 cd $\text{m}^{-2}$ were achieved in the 8 $\times $ 8 perovskite QDLEDs array display. Furthermore, an electroluminescence dynamic pattern display based on a 64-cell QDLEDs array display has been successfully demonstrated. This study demonstrates the potential of perovskite devices for next-generation displays.

Monolithic integration of display driver circuits and displays manufactured by screen printing

Here, we report all-screen printed display driver circuits, based on organic electrochemical transistors (OECTs), and their monolithic integration with organic electrochromic displays (OECDs). Both OECTs and OECDs operate at low voltages and have similar device architectures, and, notably, they rely on the very same electroactive material as well as on the same electrochemical switching mechanism. This then allows us to manufacture OECT-OECD circuits in a concurrent manufacturing process entirely based on screen printing methods. By taking advantage of the high current throughput capability of OECTs, we further demonstrate their ability to control the light emission in traditional light-emitting diodes (LEDs), where the actual LED addressing is achieved by an OECT-based decoder circuit. The possibility to monolithically integrate all-screen printed OECTs and OECDs on flexible plastic foils paves the way for distributed smart sensor labels and similar Internet of Things applications.

Pseudo Multi-Port SRAM Circuit for Image Processing in Display Drivers

N×N filter operations are frequently used in various image processing algorithms in display driver circuits. The implementation of the N×N filter requires a storage element to temporarily retain N or N-1 lines of display data. The traditional approach for this temporary storage element for N×N image filter is either by using N blocks of memory to store N lines of display data with single-port six-transistor (6T) SRAM bit-cells or by using N-1 blocks of memory to store N-1 lines of display data with dual-port eight-transistor (8T) SRAM bit-cells. In this paper, a pseudo multi-port SRAM circuit is proposed for N×N filter in image processing in a display driver integrated circuit (IC). By using pre-read mechanism and word-line/column selection signal forwarding technique, the proposed approach only stores N-1 lines of display data and can use the small single-port 6T SRAM bit-cells. For a 3×3 filter application, the proposed approach reduces the overall layout area by 50.3% and 30.2% compared to the traditional dual-port 8T and single-port 6T memory implementations, respectively, in an industrial 0.18- μm CMOS technology. Furthermore, the power used to perform a 3×3 filter operation is reduced by 47% and 30.8% with the proposed approach as compared to the traditional dual-port 8T and signal-port 6T memory circuits, respectively, with slight degradation of the access speed.

Read-Out Modulation Scheme for the Display Driving Circuits Composed of Nonvolatile Ferroelectric Memory and Oxide–Semiconductor Thin-Film Transistors for Low-Power Consumption

New circuit architecture composed of nonvolatile memory thin-film transistors (M-TFTs) and oxide–semiconductor TFTs (Ox-TFTs) has been proposed to realize low-power consumption and compact size for dynamic driving circuit applications. In order to compensate the slow operation speed of the nonvolatile M-TFTs in the dynamic driving circuits, we proposed the read-out modulation (ROM) scheme. The device operation characteristics of the M-TFTs were confirmed under various specified conditions to effectively apply the ROM, in which a top-gate structure was fabricated to be ferroelectric poly(vinylidene fluoride-trifluoroethylene) gate insulator/Al2O3/In–Ga–ZnO active layers. Full fabrication processes for the M-TFTs were optimized, so that they can be integrated with Ox-TFTs on the same glass substrate. The memory device characteristics, including the current ratios between ON- and OFF-programmed drain current ( $I_{D}$ ) values ( $I_{p-\mathrm {\mathrm{\scriptscriptstyle ON}}}/I_{p-\mathrm {\mathrm{\scriptscriptstyle OFF}}})$ before and after the ROM, drain-bias dependence of the $I_{p-\mathrm {\mathrm{\scriptscriptstyle ON}}}/I_{p-\mathrm {\mathrm{\scriptscriptstyle OFF}}}$ , and the program $I_{D}$ scalability, were confirmed for the fabricated M-TFT. These results suggest the feasibility of a low-power display driver circuit embedded with the nonvolatile M-TFTs.

AIM-Spice Integration of a Recursive Model for Threshold Voltage Shift in Thin Film Transistors

Non-crystalline semiconductor based thin film transistors are the building blocks of large area electronic systems. These devices experience a threshold voltage shift with time due to prolonged gate bias stress. In this paper we integrate a recursive model for threshold voltage shift with the open source BSIM4V4 model of AIM-Spice. This creates a tool for circuit simulation for TFTs. We demonstrate the integrity of the model using several test cases including display driver circuits.

Design and Realization of ARM-Based Technological LED Display System

the LED dot matrix is an important public information display terminal and the large screen LED display can be applied in many occasions. This article will introduce a LED display which is based on the ARM technology with S3C4510 as the core in an engineering project. In this system, the main control card module is controlled by the S3C4510. The LED display contains the display module, the control drive circuit, and the main control card module as three parts. It is a decoding system that can process a variety of picture files and video files. CPU will remove the demonstration content from the memory which is stored by the user. Then through the display driver circuit, the demonstration content can be changed into the forms signal which the LED display can accept.

A low‐power CMOS DC‐DC buck converter with on‐chip stacked spiral inductor

PurposeThe purpose of this paper is to present a fully integrated power converter. A stacked spiral inductor is applied in a voltage‐mode CMOS DC‐DC converter for the chip miniaturization and low‐power operation.Design/methodology/approachThe three‐layer spiral inductor is simulated with an equivalent circuit and applied to the DC‐DC converter. The DC‐DC buck converter has been fabricated with a standard 0.35 μm CMOS process. The power converter is measured in both experiment and simulation in terms of frequency and electrical characteristics.FindingsExperimental results show that the converter with the stacked spiral inductor operates properly with the inductance of 7.6 nH and mW power range. The measured inductance of the stacked spiral inductor is found to be almost half of the circuit designed value because of the parasitic resistances and capacitances in the spiral inductor.Originality/valueThis paper first introduces the application of the integrated stacked spiral inductor in DC‐DC buck converter for display driver circuit, which requires a low‐power operation. It also shows the fully integrated DC‐DC converter for chip miniaturization.

Generalized Modeling of Bias Voltage Compensation with Current Control for Full-Color LED Display Based on Load-Line Regulation

To give comprehensive and consecutive understanding about load line regulation in the previous companion paper [1], more generalized expansion and theoretical derivation will be proposed in this paper. The paper provides an alternative current control approach to control the bias voltage compensation for full-color LED display based on the load-line approach. Modeling and formulation of the driver circuit system will be discussed in detail. Bias voltage compensation based on three load-lines regulation will keep the operating point fixed for the three color cells. Many properties can be observed based on the proposed model. Parasite effect such as the stray resistor and the stray capacitor will be considered in this paper. The associated standard RGB color testing for color cells and white color testing will be illustrated to verify the proposed compensation for the display driver circuit. The objectives of the luminance uniformity and the gray scale control can be achieved by using circuit approach. It is believed that this paper will be helpful to the driver circuit technology for the full-color LED display.

3.3: Display Driver Circuits Fabricated on Flexible Stainless Steel Foils

AbstractThis paper discusses the design and fabrication of digital circuits (primarily shift registers) for display and other active‐matrix driving applications on flexible substrates. The unique advantages of the substrate material and their relation to circuit performance are indicated. A high temperature fabrication process for laser annealed polycrystalline silicon MOS transistors on stainless steel foils is outlined, resulting in effective mobility values up to 267cm2/Vs for n‐channel and 88cm2/Vs for p‐channel devices. Transistor CMOS inverters with a minimum propagation delay of 1.02ns per inverter stage are reported. Both static and dynamic register designs with a high degree of integration are reported, having maximum operating frequencies up to 1.5MHz and 2.5MHz respectively, at supply voltages of 10V or less. These results constitute the first realization of this level of performance and complexity on flexible substrates, and demonstrate the feasibility of high‐speed digital circuitry on thin foils suited for ‐ but not limited to‐ active matrix array driving.

Novel plasma display driver with low voltage/current device stresses

A new energy-recovery-sustain circuit suitable for a plasma display panel (PDP) application is proposed. The proposed circuit features the low device voltage/current stresses, and the inherent circulating current elimination characteristics, essential to design a power efficient and low cost plasma display driver circuit. The proposed circuit is demonstrated experimentally for driving a 42 inches plasma display panel. It is best suited in a low cost and power efficient plasma display.

Polysilicon thin-film transistors using self-aligned cobalt and nickel silicide source and drain contacts

Polysilicon thin-film transistors (TFTs) with island thickness of 20 and 70 nm were fabricated with self-aligned cobalt and nickel silicide contacts to the source and drain. The silicide contacts are shown to reduce the series resistance, which limits the on-current of the device, thus significantly increasing the effective mobility in the 20-nm island devices. The mobilities of 20-nm cobalt and nickel silicided devices are similar to those with 70-nm islands, 31 versus 33 cm/sup 2//V-s, whereas the nonsilicided 20-nm devices have a mobility of only 13 cm/sup 2//V-s. The island thickness is shown to influence other device parameters affecting active matrix display driver circuit design, such as threshold voltage, leakage current, and subthreshold swing; all these parameters are improved when the island thickness is decreased.

Low Temperature Flat Panel Display Driver Circuits in RTP Crystallized Polysilicon

AbstractThe crystallization of amorphous silicon by rapid thermal processing has some important advantages over other techniques such as laser annealing. This work investigates the characteristics of low temperature polysilicon flat panel display driver circuits fabricated in RTP crystallized polysilicon. Both digital (shift register) and analog (operational amplifier) circuits are presented.

2-MHz clocked LCD drivers on glass

A poly-CdSe thin-film transistor (TFT) liquid crystal display (LCD) driver circuit which is integrated on the display itself, reducing the interconnections to the display, is described. The circuit can be used to drive the rows as well as the columns of active and passive matrix LCDs. Drivers made in a 25- mu m technology operate at frequencies up to 2 MHz. Simulations indicate a maximum operating frequency of 8 MHz for a 12.5- mu m technology. By using a time-multiplexing addressing scheme, gray scales can be obtained. In order to address high-resolution displays with gray scales, parallel operating drivers can be used, requiring only one extra connection per parallel driver. >