白光LED的恒流驅(qū)動(dòng)電路的設(shè)計(jì)

電子機(jī)電論文編號(hào):JD1000   論文字?jǐn)?shù):18286,頁(yè)數(shù):59

目     錄
第一章 引言 1
1.1電源管理芯片的發(fā)展現(xiàn)狀及其分類(lèi) 1
1.2本課題的研究?jī)?nèi)容 3
第二章 電荷泵原理及總體結(jié)構(gòu)設(shè)計(jì) 5
2.1總體電路功能 5
2.2系統(tǒng)功能分析 5
2.2.1系統(tǒng)工作過(guò)程 5
2.2.2主要模塊功能分析 5
2.3電荷泵的設(shè)計(jì) 6
2.3.1電荷泵的介紹 6
2.3.2電荷泵升壓工作原理 7
2.3.3電荷泵降壓工作原理 9
2.4功率開(kāi)關(guān)管，電源及襯底的選擇 10
第三章 子電路模塊設(shè)計(jì)與仿真 13
3.1帶隙基準(zhǔn)電壓源 13
3.1.1基本原理 13
3.1.2電路工作原理分析 14
3.1.3仿真結(jié)果 16
3.2軟啟動(dòng)模塊 17
3.2.1電路功能描述 17
3.2.2功能特性分析 18
3.2.3簡(jiǎn)要仿真結(jié)果 20
3.3過(guò)溫保護(hù)模塊 22
3.3.1電路功能描述 23
3.3.2簡(jiǎn)要仿真結(jié)果 24
3.4欠壓鎖定（UVLO）模塊 25
3.4.1電路功能描述 25
3.4.2簡(jiǎn)要仿真結(jié)果 26
3.5過(guò)壓保護(hù)（OVP）模塊 28
3.5.1電路功能描述 28
3.5.2簡(jiǎn)要仿真結(jié)果 31
3.6誤差放大器（EA）模塊 31
3.6.1電路原理分析 32
3.6.2特性分析 34
3.6.3仿真結(jié)果 34
3.6.4討論與分析 40
3.7振蕩器（OSC模塊） 40
3.7.1電路原理分析 40
3.7.2仿真結(jié)果 42
3.8基準(zhǔn)電壓選擇(V REF60_100_300)模塊 43
3.8.1電路原理分析 44
3.8.2簡(jiǎn)要仿真結(jié)果 45
第四章 整體仿真 47
4.1瞬態(tài)仿真 47
4.2效率仿真 48
4.3電源電流與輸入電壓關(guān)系仿真 50
第五章 結(jié)論 51
參考文獻(xiàn) 52

摘要

 小型化和多功能是便攜式電子產(chǎn)品的發(fā)展趨勢(shì)，因此要求DC/DC轉(zhuǎn)換器具有高效率、低靜態(tài)電流、小的板級(jí)面積、小體積和低成本等特性。傳統(tǒng)的電源管理方法是使用電感模式的DC/DC轉(zhuǎn)換器，但是隨著業(yè)微米技術(shù)的發(fā)展和多層陶瓷大電容的使用，電荷泵的效率得到提高，所以電荷泵不僅在低功耗而且在較大輸出電流應(yīng)用中仍然得到廣泛的應(yīng)用。
    在對(duì)電荷泵原理研究的基礎(chǔ)上，論文采用0.6um標(biāo)準(zhǔn)Bi-CMOS工藝設(shè)訓(xùn)一了一種具有寬輸入電壓范圍和多電流輸出規(guī)格的恒流型電荷泵DC/DC轉(zhuǎn)換器。輸入電壓范圍為2. 7V-5. 5V，輸出電壓恒定為5. 1V，輸出電流為1. 2A, 400mA, 240mA二種規(guī)格。在空載情況下，靜態(tài)電流為5mA;在關(guān)斷情況下，靜態(tài)電流小十luA。
    本文所設(shè)計(jì)的線性電荷泵穩(wěn)壓芯片主要應(yīng)用于5. 1V的低壓供電電源。其主體架構(gòu)是由2倍的電荷泵電路與LDO線性降壓穩(wěn)壓電路組成。當(dāng)電池的供電能力不足的時(shí)候，即低于所需的額定電壓輸出值時(shí)，電荷泵將泵浦輸入電壓，最大輸出值將為輸入電壓的兩倍.這個(gè)輸出電壓經(jīng)過(guò)分壓電阻的分壓后，反饋到誤差放大器(AMP)的負(fù)極輸入端。將此電壓與基準(zhǔn)點(diǎn)壓源(REF)進(jìn)行比較，得到了被放大的誤差電壓。這個(gè)誤差電壓被用作是控制電荷泵導(dǎo)通電阻(又稱之為壓控電阻)，進(jìn)而得到了一個(gè)穩(wěn)定的輸出電壓。
    該電荷泵的優(yōu)點(diǎn)是無(wú)論輸入電源電壓高于或者低于輸出電壓，輸出電壓都能通過(guò)自動(dòng)選擇降壓或者升壓模式保持恒定。升壓和降壓模式都不需要電感元件，可提供低EMI的DC/DC轉(zhuǎn)換。高的開(kāi)關(guān)頻率允許選用小的表面陶瓷電容，可節(jié)省板級(jí)面積、降低成本和減小輸出電壓紋波。具有熱保護(hù)和電流限制功能，保護(hù)工作在不正常條件下的負(fù)載元件和芯片。輸出端通過(guò)過(guò)載比較器組成的反饋回路調(diào)節(jié)輸出電流使其穩(wěn)定.通過(guò)24mV比較器來(lái)確定電壓調(diào)節(jié)和電流調(diào)節(jié)模式。
    本文對(duì)電荷泵DC/DC轉(zhuǎn)換器的基本原理和系統(tǒng)功能作了詳細(xì)分析，首先介紹了整體結(jié)構(gòu)，然后重點(diǎn)介紹了部分子模塊電路。在電荷泵基本理論中，詳細(xì)分析了線性(Linear)模式、跳周期(SkipCycles)模式;同時(shí)也介紹了電荷泵的升壓/降壓工作原理以及主要性能參數(shù)及其意義。在子電路中，重點(diǎn)介紹了帶隙基準(zhǔn)電壓源、運(yùn)算放大器、欠壓保護(hù)、熱保護(hù)。每一個(gè)子電路分別介紹了基本工作原理、主要參數(shù)的計(jì)算方法和仿真結(jié)果。
    在電荷泵原理分析和子電路設(shè)計(jì)基礎(chǔ)上，運(yùn)用HSPICE仿真軟件對(duì)整體電路的關(guān)鍵指標(biāo)進(jìn)行了仿真并給出了詳細(xì)的仿真結(jié)果。整體仿真結(jié)果表明電荷泵的功能和重要性能指標(biāo)均達(dá)到設(shè)計(jì)要求。
關(guān)鍵詞：電荷泵，帶隙基準(zhǔn)源，運(yùn)算放大器，熱保護(hù)，欠壓保護(hù)，軟啟動(dòng)

Abstract
 The miniaturization and multi-purpose is the portable electronic products trend of development, therefore requests the DC/DC switch to have high characteristics and so on efficiency, low quiescent current, small board level area, small volume and low cost. The traditional power source management is uses the inductance pattern the DC/DC switch, but along with industry the micron technology's development and the multi-layered ceramics big electric capacity's use, the electric charge pump's efficiency has the enhancement, therefore the electric charge pump not only moreover still obtained the widespread application in the low power loss in the big output current application. To the electric charge pump principle research's foundation, the paper used 0.6um the standard Bi-CMOS craft to suppose teaches one kind to have the wide input voltage scope and the multi-electric current output specification constant flow electric charge pump DC/DC switch.
 The input voltage scope is 2. 7V-5. 5V, the output voltage constant is 5. 1V, the output current is 1. 2A, 400mA, 240mA two kind of specifications. In the idling situation, the quiescent current is 5mA; In shuts off in the situation, quiescent current small ten luA. This article designs the linear electric charge pump constant voltage chip mainly applies in 5. 1V low pressure electric power supply. Its main body construction is composed of 2 time of electric charge pump electric circuit and the LDO linear voltage dropping voltage-stabilizer circuit. When battery's power supply ability is insufficient, when namely is lower than the rated voltage value of exports which needs, electric charge pump pump input voltage, maximum output value for input voltage two times. This output voltage after voltage-division resistance differential pressure, feeds back to the erroneous amplifier (AMP) cathode input end. Press source (REF) this voltage and the reference point to carry on the comparison, obtained the error voltage which enlarges. This error voltage serves as is controls the electric charge pump breakover resistance (to call that it controls resistance pressure), then obtained a stable output voltage.
   This electric charge pump's merit is regardless of the input supply voltage is higher than or is lower than the output voltage, the output voltage can maintain constant through the automatic selection voltage dropping or the pressure-rise pattern. Pressure-rise and the voltage dropping pattern does not need the inductance part, may provide low EMI the DC/DC transformation. The high turn-on frequency permission selects the small superficial ceramics electric capacity, may save the board level area, reduce the cost and to reduce the output voltage ripple. Has the hot protection and the current limitation function, protects the work under the normal condition load part and the chip. Out-port the feedback loop adjustment output current which composes through the overload comparator causes its stable. Determines the voltage regulation and the electric current adjustment pattern through the 24mV comparator. This article has made the multianalysis to the electric charge pump DC/DC switch's basic principle and the system function, first introduced the overall construction, then introduced the partial submodule electric circuit with emphasis. In electric charge pump elementary theory, multianalysis linear (Linear) pattern, jumping cycle (SkipCycles) pattern; Simultaneously also introduced the electric charge pump's pressure-rise/voltage dropping principle of work as well as the main performance parameter and the significance. In the sub-electric circuit, introduced the band gap datum potential source, the operational amplifier, the undervoltage protection, the hot protection with emphasis. Each sub-electric circuit introduced the key job principle, the main parameter computational method and the simulation result separately. In the electric charge pump principle analysis and the sub-circuit design foundation, has carried on the simulation using the HSPICE simulation software to integrated circuit's key indicator and has given the detailed simulation result. The overall simulation result indicated that the electric charge pump's function and the important performance index achieves the design requirements.

key word: Electric charge pump, band gap datum source, operational amplifier, hot protection, undervoltage protection, soft start