Shoot‐through current reduction scheme for low power LTPS TFT programmable shift register

This paper proposes a programmable pulse width shift register where an output pulse width is adjusted only by changing a start pulse width without any additional signals and reconfiguration for the pre‐charging scheme of high resolution and high frame rate active‐matrix flat‐panel displays. In addition, the overall power consumption of a proposed circuitry is dramatically reduced by alleviating the shoot‐through current of an interval inverter, compared with the previous shift registers with the programmable or fixed output pulse width. The proposed shift register is verified by the simulation program with integrated circuit emphasis (SPICE) simulation at low temperature poly‐Si thin film transistor process for 50 stages. The proposed shift register lessens the power consumption by 34% and 54% for the output pulse widths of two and 10 line times, respectively, compared with those of the previous shift register structures.     

Letter: Dual‐mode oxide thin film transistor shift register for external compensation in active‐matrix organic light emitting diode displays

This letter describes a dual‐mode oxide thin film transistor shift register for active‐matrix organic light emitting diode displays, which provides two separate scanning and sensing pulses on one line. At a 240 Hz full‐high definition (HD) timing, estimated power consumptions are 2.44 and 2.81 mW for scanning and sensing shift registers of 16 stages at V_TH = ?1.56 V, respectively.     

Novel voltage programming n-channel TFT pixel circuit for low power and high performance AMOLED displays

This paper proposes a novel pixel circuit for high resolution, high frame rate, and low power AMOLED displays that is implemented with one driving n-channel TFT, six switching n-channel poly-Si TFTs, and a storage capacitor. The proposed pixel circuit adopts the voltage programming scheme for threshold voltage compensation. Because the whole line time is in use only for charging the data voltage, this pixel circuit is applicable to high resolution and frame rate displays. In addition, it compensates voltage variation of OLEDs and voltage drop of supply lines at lower power consumption. On the average, the non-uniformity of a proposed circuit is reduced to 2.5%, compared to 7.1% of the previous one at a 240 Hz full-HD display. On the other hand, the compensation voltage error, which is caused by feed-through and charge injection noises from falling control signals of switching TFTs, is much less in the proposed scheme than in the previous 5T2C structure. The average error of the proposed circuit is reduced to 0.18 V, compared to 0.75 V of the previous one. The initialization power consumption of the 7T1C circuit is reduced to 98 mW, compared to 530 mW of the 5T2C circuit and the average dynamic power saving ratio of data drivers is estimated in the 7T1C pixel as 98.7% over the 5T2C one for 24 test images.     

Spice model for detection of dynamic threshold voltage shift during failure analysis of oxide TFT‐based AMD gate drivers

We present an accelerated SmartSpice model that can detect dynamic threshold voltage shift (ΔV_th)‐related failure of an oxide thin‐film transistor (TFT)‐based gate driver. During gate driver operation, the alternating HIGH and LOW input signals repeatedly stress and relax the TFT components of the gate driver. Because oxide TFTs do not recover completely during the LOW input level, ΔV_th cumulated during the HIGH input levels may result in failure of gate drivers. For correct failure analysis, a TFT model that can detect dynamic ΔV_th is, therefore, needed to replace current TFT models, as they cannot account for dynamic ΔV_th. The model presented herein works correctly with varying temperature and input signals of any shape.     

High‐mobility oxide TFT for circuit integration of AMOLEDs

Abstract— A high‐mobility and high‐reliability oxide thin‐film transistor (TFT) that uses In‐Sn‐Zn‐O (ITZO) as a channel material has been developed. The mobility was 30.9 cm²/V‐sec and the threshold voltage shift after 20,000 sec of a bias‐temperature‐stress (BTS) test (with a stress condition of Vg = 15 V, Vd = 15 V, and T = 50°C) was smaller than 0.1 V. In addition, a method of obtaining a stable enhancement‐type TFT, which realizes circuit integration for active‐matrix organic light‐emitting diode (AMOLED) displays has been developed.     

A novel gate driver circuit for depletion‐mode a‐IGZO TFTs

In this paper, a novel gate driver circuit, which can achieve high reliability for depletion mode in a‐InGaZnO thin‐film transistors (TFTs), was proposed. To prevent the leakage current paths for Q node effectively, the new driving method was proposed by adopting the negative gate‐to‐source voltage (V_GS) value for pull‐down units. The results showed all the V_OUT voltage waveforms were maintained at VGH voltage despite depletion‐mode operation. The proposed circuit could also obtain stable V_OUT voltage when the threshold voltage for all TFTs was changed from ?6.5 to +11.5 V. Therefore, the circuit can achieve high reliability regardless of threshold voltage value for a‐IGZO TFTs. In addition, the output characteristics and total power consumption were shown for the alternating current (AC)–driven and direct current (DC)–driven methods based on 120‐Hz full‐HD graphics (1920 × 1080) display panel. The results showed that the AC‐driven method could achieve improved V_OUT characteristics compared with DC‐driven method since the leakage current path for Q node can be completely eliminated. Although power consumption of the AC‐driven method can be slightly increased compared with the DC‐driven method for enhancement mode, consumption can be lower when the operation has depletion‐mode characteristics by preventing a leakage current path for pull‐down units. Consequently, the proposed gate driver circuit can overcome the problems caused by the characteristics of a‐IGZO TFTs.     

基于地理信息系统的低压配电用户安全预警系统

针对目前偏远地区旅游景区配电设备常出现超负荷运行和火灾隐患的情况,本文基于地理信息系统设计了低压配电用户安全预警系统。研制了保护控制器并对各低压配电用户电气量、开关量及温度数据进行实时采集,将用户的地理位置和对应数据显示在系统中。系统对数据进行智能分析,可以实现用电安全与火灾隐患预警功能。该系统可以较好的适应旅游景区低压配电设备复杂的特点,提高低压配电网的可视化管理和信息化水平。     

低功耗霍尔电压放大器

基于霍尔传感器低功耗的要求,设计一种低功耗、可以放大微弱霍尔电压的放大器.利用MOSFET工作在亚阈区超低功耗特性,设计一种CMOS二级运算放大器.这种亚阈区放大器结构简单,工作在2.5V～3.5V电压下,电路开环增益可以达到90dB.     

A novel pixel memory using integrated voltage‐loss‐compensation (VLC) circuit for ultra‐low‐power TFT‐LCDs

Abstract— A novel pixel memory using an integrated voltage‐loss‐compensation (VLC) circuit has been proposed for ultra‐low‐power TFT‐LCDs, which can increase the number of gray‐scale levels for a single subpixel using an analog voltage gray‐scale technique. The new pixel with a VLC circuit is integrated under a small reflective electrode in a high‐transmissive aperture‐ratio (39%) 3.17‐in. HVGA transflective panel by using a standard low‐temperature‐polysilicon process based on 1.5‐μm rules. No additional process steps are required. The VLC circuit in each pixel enables simultaneous refresh with a very small change in voltage, resulting in a two‐orders‐of‐magnitude reduction in circuit power for a 64‐color image display. The advanced transflective TFT‐LCD using the newly proposed pixel can display high‐quality multi‐color images anytime and anywhere, due to its low power consumption and good outdoor readability.     

1000KW大电机低电压时间整定分析

通过理论分析计算和对实际经验的总结概括,计算了电网晃电（即电压波动）时的启动容量,确定了允许参加自启动的电动机额定容量和相对应低电压整定时间,确保了大电动机的持续运行,保证了电网的稳定.