High‐performance high‐efficiency LED‐backlight driving system for LCD panels

Abstract— A high‐performance high‐efficiency LED‐backlight driving system for liquid‐crystal‐display panels is presented. The proposed LED‐backlight driving system is composed of a high‐efficiency DC‐DC converter capable of operating over a universal AC input voltage (75–265 V) and a high‐performance LED‐backlight sector‐dimming controller. The high efficiency of the system is achieved by using an asymmetrical half‐bridge DC‐DC converter that utilizes a new voltage‐driven synchronous rectifier and an LED‐backlight sector‐dimming controller. This controller regulates current using lossless power semiconductor switches (MOSFETs). The power semiconductor switches of the proposed DC‐DC converter, including the synchronous rectifier switch, operate with zero voltage, achieving high efficiency and low switch voltage stress using the asymmetrical‐PWM and synchronous rectifier techniques. To achieve high performance, the proposed driving system performs the sector dimming and the current regulation using low‐cost microcontrollers and MOSFET switching, resulting in high contrast and brightness. A100‐W laboratory prototype was built and tested. The experimental results verify the feasibility of the proposed system.     

投影仪的LED光源驱动器的设计

介绍了在采用LED做光源的投影仪中,如何设计LED光源的驱动电路.分析了负压型Buck电路的设计及PWM调光电路、短路保护、过压保护、环路测试等问题.     

一款基于通用IC的低成本汽车日行灯HB LED驱动电路的设计

设计了一款基于通用IC LM5022的低成本汽车日行灯HB LED驱动电路,实现了HB LED的恒流驱动和PWM调光,并能满足日行灯的有关驱动要求。详细介绍了调光控制线路的设计,并对调光信号的时序和调光比影响因素等进行了分析,给出了主要实验参数和实验结果,输入电压6～19 V,输出电压40～57 V,PWM调光占空比可调5%～100%,输出LED电流200 mA,有关实验验证了本设计的可行性。     

一种用于白光LED的亮度控制电路

针对白光LED的广泛应用,要求其亮度能够方便地被调节,提出一种用于白光LED的亮度控制电路;电路只需一个亮度控制脉冲信号作为激励,就能够循环产生10位的亮度控制信号输出,控制10级亮度变化,并给出了具体应用电路,在应用时,10位输出信号控制开关管,使得流过白光LED的电流发生变化,从而控制其亮度;该电路采用0.6um的BiCMOS工艺设计,利用Hspice进行仿真验证,结果表明,电路滤除宽度小于500ns的脉冲信号,去除噪声和干扰,能够正确地循环产生10位的亮度控制信号,响应延迟为400ns。     

LED 大功率灯精准控制驱动电路设计

This paper designs a precise control drive circuit for LED high power lamp. It takes the STC89C52 single chip microcom- puter chip as the control core, selects the PT4115 as the LED power supply chip, uses the PWM to adjust the brightness mode, and re- alizes the adjustment of brightness. The LED has good characteristic of constant current, little change of light color. The circuit can be controlled by key or infrared light, and provides over-voltage and over-current protection. Through experiments, the circuit has good stability and can be adjusted by software program, which can realize multi-stage and even stepless dimming and achieve accurate dim- ming.     

LED调光控制技术在飞机导光板照明中的应用

描述了LED技术在飞机驾驶舱照明控制系统中的应用情况,针对目前民用飞机驾驶舱导光板照明普遍采用的LED电压调光技术和单纯PWM调光技术的不足,提出了改进的LED调光技术方案。新型方案利用组合调光技术和数字调光技术,弥补了传统LED调光技术的不足,并对不同的LED调光控制方案进行了分析,最后提出了LED调光技术的发展方向。     

Intercross scanning control with double driver for micro-LED display

This paper proposes a control chip for micro-light emitting diode (μLED) applied on real-time display system. The μLED control system has the video transmitter and the LED display matrix. The transmitter includes interface control, memory management, image format conversion. For LED display unit, we present the intercross scanning, memory management, PWM output controller, gamma correction for LED brightness control. TheμLED display is controlled by the intercross drivers to reduce the flicker and promote the sweeping speed with two FPGA controllers, where two parallel SPI data is adopted. The micro LED components are mounted on a PCB with mass-transfer techniques successfully. The FPGA controller can drive about 10 k light-emitting diodes with 12-bit colors for displaying system with PWM method. The passive-matrix micro LED (PMLED) driving can achieve 384 refresh rates with 50 MHz clocking frequency. The experiments result low flicker achieved, which the SVM index is only 1.5 with a photometer measurement.     

基于PWM调制的ACO-OFDM混合技术的研究

基于LED的可见光通信技术能够实现照明与无线通信的双重功能,因此被越来越多的人们所关注.但存在高PAPR、要求LED具有高线性特征及不适合发光亮度调节等问题,需要采用ACO-OFDM调制信号解决.但当转换一个振幅很小的信号时,需要更大的通信带宽,对于目前的LED显然是不能实现的.因此提出一种基于PWM调制的ACO-OF...     

基于反激式LED驱动芯片的可控硅调光设计

分析了LED驱动电源设计中的可控硅调光.设计能兼容现行大多数调光器的LED电源是降低LED成本、迅速取代当前节能照明技术的关键.系统地分析了三端双向可控硅的工作原理和LED驱动电路调光的难点,提出了加入damping电阻解决可控硅调光与LED兼容问题的方案.该设计基于AC-DC电源芯片MT7920,并加入了一种相位补偿...     

无线调控LED照明系统设计

目前家用LED多以功能性照明为主要目的．难以满足用户个性化、艺术化消费需求,为此,采用STC12LE5410AD微控制器、LT3756驱动器和nRF24L01＋．G线收发器,设计一种无线调控的LED照明系统．利用PWM调光和1KGB混色技术产生不同的光强和色温效果,实现家用LED照明的场景化控制。系统配置灵活,操作简便,性价比高,推广前景较好。     

教室智能LED照明系统设计

针对学校教室照明的舒适性、节能性以及智能化管理的需求,设计了一种新型教室智能LED照明系统。系统以PC机作为中央控制器,以PIC16F873A作为微控制器,利用RS485作为通信网络,实现整个教学楼教室LED灯的自动开/关灯和PWM调光。     

基于PWM的弱视治疗仪光源设计与实现

目前弱视治疗仪一般都采用白炽灯作为光源,利用电阻限流方式控制光强,存在发光效率低,寿命短,发热量高,体积大,可调光强级别较少,光源亮度不稳定等缺陷。针对这些缺陷,文章采用LED设计光源,利用PWM技术控制灯源光强,选择单片机AT89C52为微控制器,通过C51语言编写控制程序,对单片机输出PWM脉冲占空比进行调节,PWM脉冲直接控制驱动电路输出电流的大小,从而达到控制LED亮度强弱的目的,驱动电路的反馈设计确保了输出电流稳定,使LED光源亮度稳定,不易闪烁,比起传统白炽灯对眼睛的伤害减弱。通过实验,结果表明基于PWM技术驱动的LED光源的亮度稳定,并能提供10级以上的光强。     

大功率白光LED驱动电路的双环检测方法

基于CSMC0.5μm标准CMOS工艺,设计了一种带有双环检测的大功率LED恒流驱动芯片。仿真结果表明,芯片可在2MHz频率下工作,驱动电流最高可达1.5A,在24V电源电压时,电源效率可达95%。当电源电压在6V跳变±10%,驱动1W350mA的LED时,LED电流精度达0.02%。对比单环检测模式,该电路的LED驱动电流响应时间缩短了近2/3。此模式在保持高精度恒流和高效率的同时,有效地缩短了LED驱动电流的响应时间。     

LED backlight driving system with local dimming and scanning driver IC

Abstract— Novel LED backlight driving technology with a fully embedded LED driver IC is presented. This driving system and IC feature a high speed reduced swing differential signaling (RSDS) interface, an independent PWM controller with high‐resolution programming, and embedded scan logic. To attain high efficiency from the boost converter, highly advanced dynamic headroom control technology has been implemented onto the IC. The embedded current boosting function showed almost no brightness reduction when operated in scanning mode. The scanning function of the system improved motion blur values 26–44% compared to that of a non‐scanning LCD panel.     

Wide gamut LCD using locally dimmable four‐primary‐color LED backlight

This paper proposes a wide gamut LCD using locally dimmable four‐primary‐color (4PC) LED backlight. Although the color gamut of LCDs has been improved in recent years, it is insufficient to reproduce all the colors in the real world. The objective of this paper is to propose a wide gamut LCD that reproduces all the colors in the real world while keeping the cost increases to a minimum. We evaluated the color gamut reproduced by LEDs of multiple primary colors and selected cyan as the optimal color to be added to the three primary colors to reproduce all the colors in the real world. Therefore, we designed an LED backlight consisting of an additional only‐cyan LED with three‐primary‐color LEDs and developed a prototype LCD with 4PC LED backlight. Furthermore, we developed a local dimming algorithm for the 4PC LED backlight. As a result, we confirmed that the prototype LCD with the 4PC LED backlight is able to cover almost all the colors in the real world and also able to display natural images with highly saturated colors by local dimming.     

大功率智能RGB-LED照明系统的设计

为了满足现代照明市场的需求,设计了一款基于Android Apps控制的RGB-LED智能照明系统.该系统采用了PFC与谐振半桥联合的控制器及其共享的反馈补偿回路,通过WiFi模块与单片机、Android Apps提供可智能控制的PWM,BUCK芯片通过接收不同占空比的脉冲波形来改变输出的电流,从而实现LED灯亮度的调节.又由于不同亮度的三基色灯光可以合成自然界中的任意色光,所以该系统可以实现任意色光的合成.此设计节省了成本,提升了效率、控制精度和调光范围.通过Android Apps的功能测试,完全实现了RGB-LED灯的调光调色和情景模式的智能变换.     

恒照度调光的LED驱动器设计

随着照明技术的不断发展以及能源的日益紧张,绿色照明成为主要的研究方向。本文针对传统照明能效低、耗电量大等问题,设计了LED恒照度调光驱动器。系统使用恒流LED控制芯片NCL30160作为LED光源驱动电路,采用TSL2561光照度传感器采集室内光照度,通过处理器相应算法进行闭环控制,实现室内的恒照度调光。该算法实现了PWM波形平滑变化,避免因PWM突变造成闪光。同时,系统增加了人体运动控制,实现无人、有人时的不同调光方案,使设计进一步节能和智能化。     

多路照明LED调光控制电路的设计与实现

目前,多路照明LED正在被广 泛的应用,但每个LED都是配有一个单独的驱动源,为了能够控制多路LED的配合工作,所以进行了实验研究.实验采用的方 法是:计算机给单片机发出 调光信号,调光电路中通过C D4067来进行多路选择,单片机产生PWM调节电流值,其中调光电路又采用了调解工作电流方式和脉宽调制方式两种 方法.通...     

LED隧道照明智能控制系统

为了解决驾驶员在穿越隧道时的眩光效应和节约隧道照明电能,利用LED灯启动时间短和恒流驱动的优点,设计了大功率LED隧道照明控制系统。对系统的控制策略和工作原理进行了详细介绍。系统设有自动、手动和应急等3种工作模式,满足了不同应用的需要。在手动模式下,对系统进行了验证,结果表明该控制系统不仅可以实时精确地连续调光,而且调光范围可达到0~100%。     

HB-LED医用手术头灯控制系统的设计与实现

研制了以高亮度LED为光源的医用手术头灯控制系统。该系统由电源路径管理电路、充电管理电路、LED驱动电路和调光电路组成。采用外部电源或者电池双电源供电,可驱动5W的大功率白光LED,同时具备LED亮度连续调节和电池充电管理等功能。LED亮度调节实验和锂电池充电实验表明该控制电路很好地符合了预期的设计要求,LED控制电路具有很强的通用性,体积小、价格低廉,适合于便携式电子产品的设计应用。