共查询到20条相似文献,搜索用时 78 毫秒
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LED由于环保、寿命长、低耗电量等特性,近年来在各行业得以快速应用及发展,LED驱动电路的研究与设计也成了关注热点。通过设计升压式DC-DC转换芯片,采用PWM控制方式和电流控制模式,对外接串联的LED进行驱动。然后用Spectre软件完成了总体电路的模拟和仿真,通过对其结果分析,表明系统能够稳定工作,并且达到设计指标要求。 相似文献
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目前,很多制造商正在促进白光LED驱动电路的产品化,十几家公司在生产应用于L C D的背光LED驱动芯片。为了得到更清晰的画面,厂商增加了驱动背光白光LED的能力。很多的产品,用单个芯片能够驱动4个以上的白光LED。白光LED驱动芯片市场的价格竞争非常激烈。大多数产品的平均单价是 相似文献
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引言随着目前市场上移动电话、便携电子产品等大量采用彩色液晶显示屏的趋势不断增长,各厂商也纷纷对用于彩色LCD显示屏背景光源的白色LED给予了更高的关注。本文介绍LinearTechnology 公司的LT1937升压型白光LED驱动器的性能特点、驱动电路及其调光控制方式。LT1937的性能特点LT1937升压型白光LED驱动器是一种适用于蜂窝电话、PDA和数码相机等采用小型电池供电的便携式设备中背光照明的理想解决方案,能提供较高的发光效率和均匀的LED亮度。其主要的性能特点有:(1) 具有一个能驱动多达8个串联LED的内部36V开关,并对采用锂电池供… 相似文献
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Lianxi Liu Yue Niu Jiao Zou Zhangming Zhu Yintang Yang 《Analog Integrated Circuits and Signal Processing》2014,79(1):37-44
This paper presents a hysteretic-current-control LED driver with the dual dimming mode. This novel monolithic driver includes an output switch and a high-side output current sensing circuit using an external resistor to set the nominal average output current (IOUTnom). By applying an external control signal to the DIM pin, it can alter flexibly the control mode between the analog (DC) and switching (PWM) dimming. In the DC dimming mode, when the input DC control voltage is adjusted from 0.5 to 2.5 V, the average output current can be changed from 20 to 100 % of the current IOUTnom. While in the switching dimming mode, the output current is proportional to the duty cycle of the input switching signal and changed from about 0 to 100 % of the current IOUTnom. The driver circuit has been verified in a 0.5 μm HVCMOS process and the die size is about 1.2 × 1.5 mm2. This proposed driver can work in 8–40 V power supply, the maximum average output current is up to 1.0 A. 相似文献
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白色LED驱动器的发展概况 总被引:1,自引:0,他引:1
白色LED是小型彩色LCD背光照明的最佳选择,这是因为它能使LCD色彩更逼真、色度更饱和,并且电路简单、占印制板体积小、耗电省、价格较便宜的缘故.近年来,手机不断更新换代,普及率越来越高,数码相机大有取代传统相机之势,促使白色LED及其驱动器的产量猛增.为满足不同输入电压、不同的输出电流及不同的LED数等要求,各半导体器件公司纷纷开发出各种新型白色LED驱动器(以下简称驱动器)以满足市场的需要. 相似文献
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John Jovalusky 《今日电子》2007,(6):69-70,75
白炽灯灯泡发展至今已接近极限,其95%的热损耗使很多用户大伤脑筋.相比之下,荧光灯的表现虽然稍微好点,但功耗浪费仍高达80%.这两种技术均无法与白光LED同日而语,其在理论上已具备80%以上的能效水平. 相似文献
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This paper discusses theoretical analysis of the efficiency of a light emitter diode (LED) driver using a charge pump. It is shown that the maximum efficiency of a conventional LED driver using a charge pump is determined only by the ratio of a forward voltage of an LED and a nominal output voltage of a charge pump. Theoretical analysis reveals that the efficiency does not depend on values of flying capacitors and output capacitors, clock frequency, duty cycle and on-resistance of switches. Minimizing the difference of an output voltage of a charge pump and a forward voltage of an LED is important to minimize power loss of an LED driver. In order to reduce power loss caused by charging capacitors, a novel charging procedure named multi-step charging technique is proposed. Some charge pumps using multi-step charging technique are shown and validity of the proposed multi-step charging technique is confirmed. 相似文献
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为了满足LED驱动在宽电压范围内的性能,设计了一种基于Boost-Buck PFC电路的LED驱动器.当输入交流电压变化范围较宽时,PFC的输出依然可以稳定在较低值,可确保功率器件始终保持较小的开关应力.同时,为了满足LED的调光功能,并确保大功率照明场合LED串并联应用的稳定性,各LED并联支路增加了独立调光模块,可根据不同的应用场合工作在独立线性调光、独立PWM调光以及线性PWM复合调光模式,并且通过电流和温度信息的采集各支路可实现自动均流.最后以两路LED并联为基础,搭建实验样机,实现了各支路之间的独立调光以及自动均流. 相似文献
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A high performance white light emitter diode (LED) driver based on boost converter with novel single-wire serial-pulse digital dimming (SWSP) is proposed. The driver uses external serial programmed pulses and internal clock to simplify brightness control. By embedding a 5-bit digital analog converter (DAC) into the driver, wide dimming range is achieved. Moreover, a new dynamic slope compensation circuit is presented and other key circuits of the driver are optimized to get higher efficiency and fast transition response. A practical circuit is implemented with 0.6 um bipolar complementary-metal-oxide-semiconductor double-diffused-metal-oxide-semiconductor (BCD) technology. The simulation results show that the driver can provide both wide output current from 1.3 mA to 42 mA with 32-level digital dimming and higher efficiency up to 83% while it works at 1 MHz switching frequency with the input voltage variation from 2.7 V to 5.5 V. 相似文献