一种用于LCD驱动的低功耗输出缓冲放大器

在AB类输出级的基础上,结合正反馈辅助的B类输出级,提出了一种用于LCD驱动电路的大输出摆率、低功耗的输出缓冲放大器。在0.15μm高压CMOS工艺模型下,该放大器能够驱动0～20nF范围的容性负载,静态电流为7μA,1%精度建立时间小于6μs,满足了LCD驱动电路行建立时间的要求;通过采用共源共栅频率补偿结合输出零点补偿技术,较好地满足了大动态范围容性负载的要求。     

一种窄边框的液晶显示面板设计

为了满足市场对LCD面板高分辨率、窄边框的需求,面板设计引入了玻璃上集成栅极驱动设计。本文对传统液晶显示面板栅极电路设计做了介绍,分析了集成栅极驱动电路技术在实现显示面板窄边框化时的优缺点。提出了一种新型栅极驱动电路,将空间控制转化为时间控制,使用一条栅极走线控制两行甚至多行像素。模拟分析结果表明:新型栅极驱动电路在关态下会产生2.5V的较小噪声;栅极信号的上升沿及下降沿的时间延迟总和只有3.5μs,可以实现像素节点的正常充放电并完成显示面板的正常显示。同时,本文提出的新型驱动电路可成倍减少显示面板边框栅极走线数量,减少栅极走线所占用的空间,实现高分辨率高解析度显示面板的窄边框化设计。     

一种非晶硅薄膜晶体管栅极驱动电路

非晶硅薄膜晶体管(Amorphous Silicon Thin Film Transistors,a-Si TFT)具有器件性能均匀、成本低、适用于大面积显示的优点,是平板显示技术的主流基板材料。近年来由于集成栅极驱动电路(Gate Drivers Integrated in Array,GIA)在非晶硅薄膜晶体管液晶显示器中的应用,不仅能节省工艺步骤,降低成本,而且边框美观对称,使非晶硅薄膜晶体管液晶显示屏更加受到消费者的欢迎。但是由于非晶硅电子迁移率相对较低,栅极驱动电路仍占用较大空间,尤其是随着显示产品解析度的增加,产品边框变窄,驱动电路的版图空间变小,导致驱动电路的设计越来越困难。文章提出了一种新型栅极驱动电路,有效提高了a-Si TFT GIA的驱动能力,降低了版图面积,增加了a-Si TFT在高分辨、窄边框产品市场的竞争力。     

面向电荷泵的占空比可调四相时钟发生电路北大核心

针对传统四相时钟发生电路产生的时钟波形信号易发生交叠、驱动电荷泵易发生漏电等问题，提出了一种占空比可调四相时钟发生电路。电路在每两相可能出现交叠的时钟信号之间都增加了延时单元模块，通过控制延时时间对输出时钟信号的占空比进行调节，避免了时钟相位的交叠。对延时单元进行了改进，在外接偏置电压条件下，实现了延时可控。基于55 nm CMOS工艺的仿真结果表明，在10～50 MHz时钟输入频率范围内，该四相时钟发生电路可以稳定输出四相不交叠时钟信号，并能在1.2 V电压下驱动十级电荷泵高效泵入11.2 V。流片测试结果表明，该四相时钟发生电路能够产生不相交叠的四相时钟波形，时钟输出相位满足电荷泵驱动需求。     

VHF频段小型化千瓦级GaN功率放大器

为了满足VHF频段对高功率放大器小型化的需求，设计并制备了一款基于0.5μm GaN高电子迁移率晶体管(HEMT)工艺的VHF频段小型化千瓦级功率放大器。通过采用多节微带电容网络和高介电常数的印制电路板(PCB)实现了末级功率放大器匹配电路的小型化；以高通滤波器作为级间匹配电路，在减小电路尺寸的同时，提高了链路增益；采用混合集成工艺，实现了电源调制器、前级驱动功率放大器和末级功率放大器等各单元的小型化高密度集成。测试结果表明，在0.24～0.30 GHz频带内，该功率放大器的工作电压为50 V,工作脉宽为100μs,在占空比10%、输入功率10 dBm的工作条件下，带内输出功率大于1 000 W,功率附加效率约为60%～69%,功率增益大于50 dB,功放体积为46 mm×30 mm×6 mm。     

高增益S波段小型化200 W功率模块研制技术

采用多级射频放大电路以及高压脉冲调制技术,实现了S波段高增益小型化200 W功率模块的研制。驱动放大电路采用GaAs功率单片进行功率合成;末级放大电路依托栅长(0.5 μm) GaN高电子迁移率晶体管(HEMT)芯片,选取多子胞结构来改善热分布,通过内匹配技术设计完成了双胞总栅宽24 mm GaN芯片的匹配网络,并设计高压脉冲调制电路提供电源,成功研制出了小型化的S波段200 W内匹配GaN功率模块。测试得出该模块实现了在输入功率10 dBm,栅极电压-5 V,漏极电压32 V,TTL调制信号输入条件下,输出频率在3.1~3.5 GHz处,输出功率大于200 W,功率附加效率(PAE)大于55%。模块实际尺寸为2.4 mm×38 mm×5.5 mm。     

基于FPGA的大屏幕FED视频驱动控制系统的研制

论述基于FPGA的FED视频驱动显示控制系统的工作原理,包括了视频采集控制模块、缓存模块、时钟控制模块、集成灰度调制控制模块以及行集成控制模块等的FPGA控制技术。研制出了FED显示器样机,能显示彩色视频图像。样机亮度已达200cd/m2、对比度达600:1,显示分辨率为480×240,电路灰度等级达256级,有效显示对角线尺寸为25in。     

移动液晶显示屏用集成a-Si行驱动电路技术

利用标准TFT工艺,开发了集成a-Si行驱动(ARD)电路技术的5 .08 cm(2 .0 in)和4 .57 cm(1 .8 in)移动液晶显示屏。通过整合RGBWPenTile矩阵技术和AFFS技术,可以获得很低功耗;应用球形玻璃纤维和优化的电路能够得到非常窄的暗区。综合运用上述技术,我们就有可能将ARD面板运用于移动液晶显示屏。     

应用于Flash存储器的一种高效低纹波电荷泵设计

针对交叉耦合型电荷泵电荷回流的问题,本文提出了一种新型六相位电荷泵结构,电荷泵的主体由3个NMOS管和3个泵电容组成。考虑到时钟驱动能力对电荷泵性能的影响,设计通过增加额外的时钟驱动模块实现四相位到六相位的时钟转换,从而减小电荷泵的上升时间并改善输出电压。此外,电路采用并联双支路结构减小输出电容的充放电时间间隔,以减小输出纹波。基于0.13μm工艺的仿真结果表明,在时钟频率为20MHz,负载电容为50pF,负载电流为300μA的条件下,该电路可以实现3.3V到15V的电压转换,效率可达到67.7%,输出纹波仅为38.5mV。     

用于高速CMOS图像传感器的锁相环模块

随着CMOS图像传感器(CIS)向片上系统化、高度集成化方向发展,片内锁相环(PLL)成为系统不可或缺的片上时钟模块,而高速高集成的CIS对PLL的高频时钟输出能力提出了新的挑战。介绍了一种基于0.13μm CIS工艺设计的电荷泵PLL模块,该模块工作于1.5V电压,利于控制功耗;具备压控振荡器(VCO)电流自偏置和自校准技术,可提供最高频率为480MHz的输出信号和更好的噪声性能;多种输入输出倍频可选功能使其能够满足多样化的片上时钟生成需求,提高可复用性。仿真结果表明,当实现12倍频且输出频率为480MHz时,该PLL模块输出信号的均方根周期抖动为837fs,功耗为2.817mW,满足高速CIS对时钟速度的需求,同时保证了输出时钟的低噪声和模块本身的低功耗。     

Enhancement of Brightness Uniformity by a New Voltage-Modulated Pixel Design for AMOLED Displays

This letter presents a new pixel design and driving method for active-matrix organic light-emitting diode (AMOLED) displays using low-temperature polycrystalline silicon thin-film transistors (TFTs). The proposed pixel circuit consists of five TFTs and one capacitor to eliminate the variation in the threshold voltage of the TFTs, and the drop in the supply voltage in a single frame operation by the source-follower-type connection and the bootstrap. The proposed pixel circuit has been verified to realize uniform output current by the simulation work using the HSPICE software. The novel pixel design has great potential for use in large-size and high-resolution AMOLED displays.     

A New Pixel Circuit Compensating for Brightness Variation in Large Size and High Resolution AMOLED Displays

A new pixel design and driving method for active-matrix organic light-emitting diode (AMOLED) display using low-temperature polycrystalline silicon thin-film transistor (LTPS-TFT) is proposed. The new circuit consists of five TFTs and one capacitor to eliminate the variation in the threshold voltage of the TFTs, and the drop in the supply voltage in a single frame operation. The proposed pixel circuit has been verified to realize uniform output current by the simulation work using HSPICE software. The simulated error rate of the output current is also discussed in this paper. The novel pixel design has great potential for use in large size and high resolution AMOLED displays.     

Novel TFT-Based emission driver in high performance AMOLED display applications

A novel integrated row driver for emission control with n-type thin-film transistors (TFTs) was proposed. A single stage of the proposed driving circuit consists of charge supplement unit, improved inverter, and power conservation unit besides input TFT and driving TFTs. Simulations were carried out with fabricated LTPS TFT. The results show the driving circuit achieves leakage prevention with no floating state and high reliability even under the V_th shift of 3 V. What's more, further measurement results show a 3 μs pulse width can be generated by the circuit, supporting 8k4k resolution with high refresh rate of 120 Hz. And the capability of low refresh rate (1 Hz) driving also can be achieved without degradation. In addition, only three control signals (two non-overlap clocks and one input signal) are used in the proposed circuit, where input signal of present stage is connected with the output of its previous stage. That means the row driver can work under independent control and be not susceptible, which contributes to generating adjustable pulse width for pulse width modulation (PWM) in active matrix organic light-emitting diode (AMOLED) displays.     

基于P-Type多晶硅TFT技术的集成型有源OLED驱动电路

低温多晶硅(LTPS:Low-temperature poly-Si)技术已经成为薄膜晶体管(TFT:thin film transistor)制作中最具吸引力的技术,并应用在AMOLED显示器中.P-type 技术能够简化 TFT 的制作过程.本文提出了一种应用 p-type 多晶硅 TFT的 AMOLED 驱动电路结构,包括栅极驱动器、数据驱动器以及像素阵列.数据驱动器采用分块方法,使得显示屏的输出线数大大减少.作者采用一种改进的 p-type 移位寄存器实现逐行选通的功能,并采用由 4 个 p-type 反相器级联构成的缓冲器来提高电路的驱动能力.为了验证上述电路结构的正确性,作者采用 HSPICE 软件进行仿真分析.结果表明,电路工作正常.利用韩国汉城国立大学及 Neo Poly 公司在多晶硅制作方面的优势,我们已经合作完成了应用上述电路结构的分辨率为96×3×128的有源 OLED 的制作.     

Improved a-Si:H TFT pixel electrode circuits for active-matrixorganic light emitting displays

Two improved four thin-film-transistors (TFTs) pixel electrode circuits based on hydrogenated amorphous silicon (a-Si:H) technology have been designed. Both circuits can provide a constant output current level and can be automatically adjusted for TFT threshold voltage variations. The circuit simulation results indicate that an excellent linearity between the output current and input current can be established. An output current level higher than ~5 μA can be achieved with these circuits. This current level can provide a pixel electrode brightness higher than 1000 cd/m² with the organic light-emitting device (OLED) having an external quantum efficiency of 1%. These pixel electrode circuits can potentially be used for the active-matrix organic light-emitting displays (AM-OLEDs)     

A low-power high-speed class-AB buffer amplifier forflat-panel-display application

A low-power, high-speed, but with a large input dynamic range and output swing class-AB output buffer circuit, which is suitable for flat-panel display application, is proposed. The circuit employs an elegant comparator to sense the transients of the input to turn on charging/discharging transistors, thus draws little current during static, but has an improved driving capability during transients. It is demonstrated in a 0.6 μm CMOS technology     

Modular current-mode multiple input minimum circuit for fuzzy logiccontrollers

A new current-mode multiple input minimum circuit designed with 4n+1 transistors for n inputs is proposed. Not only is the problem of accumulated errors solved, but the operation speed is also increased owing to the proposed multiple input minimum circuit having a one stage structure. This circuit had been fabricated using 0.8 μm CMOS technology. Experimental results have verified the function of the circuit and shown the merit of high accuracy and a large dynamic range     

High-speed low-power voltage-programmed driving scheme for AMOLED displays

A new voltage-programmed driving scheme named the mixed parallel addressing scheme is presented for AMOLED displays, in which one compensation interval can be divided into the first compensation frame and the consequent N-1 post-compensation frames without periods of initialization and threshold voltage detection. The proposed driving scheme has the advantages of both high speed and low driving power due to the mixture of the pipeline technology and the threshold voltage one-time detection technology. Corresponding to the proposed driving scheme, we also propose a new voltage-programmed compensation pixel circuit, which consists of five TFTs and two capacitors(5T2C). In-Zn-O thin-film transistors(IZO TFTs) are used to build the proposed 5T2C pixel circuit. It is shown that the non-uniformity of the proposed pixel circuit is considerably reduced compared with that of the conventional 2T1C pixel circuit. The number of frames(N) preserved in the proposed driving scheme are measured and can be up to 35 with the variation of the OLED current remaining in an acceptable range. Moreover, the proposed voltage-programmed driving scheme can be more valuable for an AMOLED display with high resolution, and may also be applied to other compensation pixel circuits.     

一种基于低温多晶硅薄膜晶体管的交流AMOLED像素补偿电路

This paper presents a new poly-Si pixel circuit employing AC driving mode for active matrix organic light-emitting diode （AMOLED） displays. The proposed pixel circuit, which consists of one driving thin-film tran- sistor （TFT）, three switching TFTs, and one storage capacitor, can effectively compensate for the threshold voltage variation in poly-Si and the OLED degradation. As there is no light emission, except for during the emitting period, and a small number of devices used in the proposed pixel circuit, a high contrast ratio and a high pixel aperture ratio can be easily achieved. Simulation results by SMART-SPICE software show that the non-uniformity of the OLED current for the proposed pixel circuit is significantly decreased （〈 10%） with an average value of 2.63%, while that of the conventional 2T1C is 103%. Thus the brightness uniformity of AMOLED displays can be improved by using the proposed pixel circuit.     

具有顶部发光结构的AMOLED交流驱动电路

A new voltage programmed pixel circuit with top emission design for active-matrix organic lightemitting diode(AMOLED) displays is presented and verified by HSPICE simulations.The proposed pixel circuit consists of five poly-Si TFTs,and can effectively compensate for the threshold voltage variation of the driving TFT.Meanwhile,the proposed pixel circuit offers an AC driving mode for the OLED by the two adjacent pulse voltage sources,which can suppress the degradation of the OLED.Moreover,a high contrast ratio can be achieved by the proposed pixel circuit since the OLED does not emit any light except for the emission period.