【摘要】：隨著溫室效應(yīng)、能源危機(jī)以及生態(tài)環(huán)境的日益惡化,使得人們迫切希望能改變能源的獲取方式以及提高能源利用率。在此背景下,發(fā)光二極管(LED,Light Emitting Diode)以其亮度高、高效能、壽命長,耗能低,污染小以及出色的色譜性能等優(yōu)勢進(jìn)入人們的視野,它將代替白熾燈、高壓氣體放電燈和熒光燈等傳統(tǒng)光源而成為新一代電光源。LED在眾多方面的應(yīng)用,極大推動了LED驅(qū)動芯片的研究與發(fā)展。然而LED的核心結(jié)構(gòu)是PN結(jié),其I-V特性曲線呈非線性關(guān)系,故電壓的微小變化將引起LED電流的很大變化,嚴(yán)重時會導(dǎo)致白光LED的色彩也跟著發(fā)生變化。為了避免色彩的偏移和確保亮度的穩(wěn)定,LED應(yīng)當(dāng)用恒流驅(qū)動。本文首先介紹了LED的一些特性,發(fā)光機(jī)理,連接方式,然后詳細(xì)分析了各種常見LED驅(qū)動電路的原理以及各自的特性,接著對目前常使用的恒流IC系統(tǒng)方案進(jìn)行分析,根據(jù)系統(tǒng)設(shè)計指標(biāo)的要求,提出了本文的整體電路設(shè)計架構(gòu),結(jié)合整體電路的功能完成了以下幾個關(guān)鍵子模塊電路的設(shè)計,包括基準(zhǔn)電壓源電路、恒定電流源電路、輸出驅(qū)動級電路以及溫度保護(hù)電路。在詳細(xì)分析模塊電路的工作原理的基礎(chǔ)上,運用Cadence仿真軟件對子電路進(jìn)行了功能驗證和性能參數(shù)的仿真。然后對整體電路進(jìn)行仿真和版圖設(shè)計。本次采用了CSMC 0.8μm工藝制造,輸入電壓范圍3.5V~6V,輸出電流可根據(jù)實際需求做調(diào)整,且輸出電流不隨電源電壓變化,在溫度-40℃~125℃范圍內(nèi)有著很好的溫度特性;輸出端可以承受10V的電壓,以滿足多個LED串聯(lián)的需求。與傳統(tǒng)的恒流多通道LED驅(qū)動器相比,該結(jié)構(gòu)具有良好的多通道驅(qū)動能力,較高的電流匹配精。
[Abstract]:With the Greenhouse Effect, the energy crisis and the worsening of the ecological environment, people are eager to change the way of energy access and improve energy efficiency. In this context, LED,Light Emitting Diode) (Light emitting Diode), with its advantages of high brightness, high efficiency, long life, low energy consumption, low pollution and excellent chromatographic performance, will replace incandescent lamps. High voltage gas discharge lamp and fluorescent lamp have become the new generation of electric light source. The application of LED in many aspects has greatly promoted the research and development of LED driver chip. However, the core structure of LED is PN junction, and its I-V characteristic curve is nonlinear, so the small change of voltage will cause a great change of LED current, and the color of white LED will also change. To avoid color offsets and ensure brightness stability, LED should be driven by constant current. In this paper, the characteristics, luminescence mechanism, connection mode of LED are introduced, then the principle of various common LED driver circuits and their characteristics are analyzed in detail, and then the current constant-current IC system scheme is analyzed. According to the requirements of the system design index, this paper puts forward the overall circuit design architecture, and completes the design of the following key sub-module circuits, including the reference voltage source circuit, the constant current source circuit, combined with the function of the whole circuit. Output drive stage circuit and temperature protection circuit. Based on the detailed analysis of the working principle of the module circuit, the function verification and the performance parameter simulation of the sub-circuit are carried out by using the Cadence simulation software. Then the whole circuit simulation and layout design. The output current can be adjusted according to the actual demand, and the output current does not change with the supply voltage. The output current has a good temperature characteristic in the temperature range of -40 鈩，

本文編號：2265202