【正文】 壓的目的。 直流穩(wěn)壓電源的分類 直流穩(wěn)壓電源的發(fā)展已有幾十年的歷史，已從分立器件發(fā)展到集成電路。為了提高電子設(shè)備的精度及穩(wěn)定性，在直流電源中還要加入穩(wěn)壓電路，因此稱為直流穩(wěn)壓電源。電壓檔位選擇開關(guān) K1 選用 2X9 的小型波段開 關(guān)。電源變壓器 T 的功率要大于 300V。為了解決這個問題，在 LM337 的輸入端加入了由 VT1 組成的輸入電壓限制電路，實際上就是一個射極跟隨器，用這個電路保證 5 LM337 的輸入輸出電壓差最高為 5V，從而避免 了因過電壓損壞集成電路。不但降低了穩(wěn)壓集成電路的損耗，而且提高了最大輸出電壓。當(dāng)電源輸出電壓較低、電流比較大時，功耗全部消耗在 LM337 上，造成集成電路發(fā)熱嚴(yán)重。 穩(wěn)壓電源的核心元件是 LM337，它是一片大電流可調(diào)穩(wěn)壓集成電路。 3）體積小重量輕 開關(guān)電源可將電網(wǎng)輸入的交流電壓直接整流再進(jìn)行 PWM控制，這樣可省去笨重的電源變壓器 (為了和高頻變壓器相區(qū)別，電源變壓器又稱為工頻變壓器 )，使電源的體積大大縮小，重量減輕。功耗小使得機(jī)內(nèi)溫升亦低，周圍元件不會因長期工作在高溫環(huán)境下而損壞，有利于提高整機(jī)的可靠性和穩(wěn)定性。很大的浪涌電流 ,這個浪涌電流可以為正常輸入電流的數(shù)倍。 二、程序保護(hù)開關(guān)穩(wěn)壓電源的電路比較復(fù)雜 ,基本上可以分為小功率的控制部分和大功的開關(guān)部分。簡單的極性保護(hù)電路如圖 1 所示。 一、極性保護(hù) 直流開關(guān)穩(wěn)壓器的輸入一般都是未穩(wěn)壓直流電源。最簡單的極性保護(hù)電路如圖 1 所示。 電路的誤差分析與改進(jìn) ...........................................................................16 附表：見最后 3 第一章 直流穩(wěn)壓器原理 直流開關(guān)穩(wěn)壓器的輸入一般都是未穩(wěn)壓直流電源。 ................................................................................. 9 .............................................................................................10 ................................................................................................. 9 ................................................................................................10 ................................................................................................10 .............................................................12 167。 ............................................................................................... 9 167。 直流穩(wěn)壓電源的構(gòu)成 ................................................................................ 6 167。保護(hù)電路的種類很多 ,這里介紹極性保護(hù)、程序保護(hù)、過電流保護(hù)、過電壓保護(hù)、欠電壓保護(hù)以及過熱保護(hù)等電路。本文主要以半橋變換電路為開關(guān)電源的主電路，設(shè)計一臺品質(zhì)優(yōu)良的直流開關(guān)穩(wěn) 壓電源。直流穩(wěn)壓電源高頻化是其發(fā)展的方向，高頻化使開關(guān)電源小型化，并使直流穩(wěn)壓電源進(jìn)入更廣泛的應(yīng)用領(lǐng)域，特別是在高新技術(shù)領(lǐng)域的應(yīng)用，推動了高新技術(shù)產(chǎn)品的小型化、輕便化。因而開關(guān)穩(wěn)壓器的保護(hù)應(yīng)該兼顧穩(wěn)壓器本身和負(fù)載的安全。 關(guān)鍵詞： 穩(wěn)壓器 半橋變換電路 數(shù)學(xué)模型 應(yīng)用價值 abstract of a thesis Dc regulated power supply with the characteristics of high efficiency, small volume, light weight, obtained the rapid development in recent years. Dc regulated power supply high frequency is its development direction, high frequency, the miniaturization of switch power supply, dc regulated power supply and to enter into a wider range of application fields, especially in the high and new technology in the field of application, promoted the hightech products of miniaturization, light change. This article mainly to transform half bridge circuit for the main circuit of switching power supply, design a high quality of dc regulated power supply switch. Dc switching voltage stabilizer used in highpower switching devices more expensive, the control circuit is also more plex, in addition, the switching voltage stabilizer load is usually with a high degree of large integrated device installed electronic systems. The transistor and the integrated device resistance electric and thermal shock ability is poor. Thus switching voltage stabilizer protection should take into account voltage regulator itself and the safety of the load. Many different kinds of protection circuit, introduced here polarity protection, procedure protection, over current protection, overvoltage protection, under voltage protection and overheat protection circuit. Usually chooses to bine several protection methods, improve the protection of the system. Dc regulated power supply high longterm stability is mainly affected by temperature, this paper analyses the position of dc regulated power supply high principle, has established the mathematical model of temperature stability, accurate and feasible quantita