【正文】 壓電流指標(biāo)精度高 SFR9034； STC12C5608AD； Nokia5110； AD 采樣； Abstract The system is posed of the macro crystal technology group of 8 bit high speed and low power STC12C5608AD microcontroller as control core, resulting in two PWM to drive the switch tube SFR9034 MOS tube with builtin AD as feedback, make DCDC power two controllable, and Nokia5110 LCD screen to display the current value of the current voltage value, when changing the load, to to control the output voltage by changing PWM, stable output is about 8V, and then through the current SCM algorithm to calculate the DCDC module and the total. According to the design requirements, adjust again PWM, so that the current distribution, at the same time in the process of sampling current, can do the flow limiting control, to protect the role. DC regulated power supply as the DC energy providers, in various kinds of electronic equipment, has an extremely important position, its performance is good or not directly affect the entire electronic products, precision, stability and U with the electronic technology development power technology also obtained the very big development, it is from the past a less plicated electronic circuits into today has the strong function of of stable power supply way, by traditional linear development to today39。s switching regulated power supply technology from in the past, attached to other electronic equipment state, gradually evolved into a separate branch of electronic science. The power of modern technology is the application of power electronic semiconductor devices, automatic control, puter (microprocessor) technology and electromagic technology and multidisciplinary cross all kinds of high quality, high efficiency, high reliability of the power play a key role, is the modern power electronics technology regulated power supply has the advantages of stable performance, simple structure, convenient adjustment, the practical advantages of a wide range of applications. [Key words] DC regulated power supply bridge rectifier circuit and filter circuit voltage stabilizing DC regulated power supply fullwave rectifier capacitance filter integrated three terminal voltage of 39v DC output voltage and current of high precision display circuit indicator 前 言 當(dāng)今社會人們極大的享受著電子設(shè)備帶來的便利，但是任何電子設(shè)備都有一個共同的電路 —— 電源電路。大到超級計算機(jī)、小到袖珍計算器，所有的電子設(shè)備都必須在電源電路的支持下才能正常工作，當(dāng)然這些電源電路的樣式、復(fù)雜程度千差萬別。超級計算機(jī)的電源電路本身就是一套復(fù)雜的電源系統(tǒng)，通過這套電源系統(tǒng)，超級計算機(jī)各部分都能夠得到持續(xù)穩(wěn)定、符合各種復(fù)雜規(guī)范的電源供應(yīng)。袖珍計算器則是簡單多的電池電源電路，不過你可不要小看了這個電池電源電路，比較新型的電路完全具備電池能量提醒、掉電保護(hù)等高級功能?？梢哉f電源電路 是一切電子設(shè)備的基礎(chǔ)，沒有電源電路就不會有如此種類繁多的電子設(shè)備，我們的生活也就不會這么豐富多彩了。 由于電子技術(shù)的特性，電子設(shè)備對電源電路的要求就是能夠提供持續(xù)穩(wěn)定、滿足負(fù)載要求的電能，而且通常情況下都要求提供穩(wěn)定的直流電能。提供這種穩(wěn)定的直流電能的電源就是直流穩(wěn)壓電源，直流穩(wěn)壓電源在電源技術(shù)中占有十分重要的地位。 直流穩(wěn)定電源按習(xí)慣可分為化學(xué)電源、線性穩(wěn)定電源和開關(guān)型穩(wěn)定電源，它們又分別具有各種不同類型： （ 1）化學(xué)電源：平常所用的干電池、鉛酸蓄電池、鎳鎘、鎳氫、鋰離子電池均屬于這一類，各有其優(yōu)缺 點(diǎn)。隨著科學(xué)技術(shù)的發(fā)展，又產(chǎn)生了智能化電池；在充電電池材料方面，美國研制員發(fā)現(xiàn)錳的一種碘化物，用它可以制造出便宜、小巧、放電時間，多次充電后仍保持性能良好的環(huán)保型充電電池。 （ 2）線性穩(wěn)壓電源：線性穩(wěn)定電源有一個共同的特點(diǎn)就是它的功率器件調(diào)整管工作在線性區(qū)，靠調(diào)整管之間的電壓降來穩(wěn)定輸出。由于調(diào)整管靜態(tài)損耗大，需要安裝一個很大的散熱器給它散熱 ,而且由于變壓器工作在工頻（ 50Hz)上 ,所以重量較大。該類電源優(yōu)點(diǎn)是穩(wěn)定性高，紋波小，可靠性高，易做成多路，輸出連續(xù)可調(diào)的成品；缺點(diǎn)是體積大、較笨重、效率相對較 低。 （ 3）開關(guān)型直流穩(wěn)壓電源：電路型式主要有單端反激式，單端正激式、半橋式、推挽式和全橋式。它和線性電源的根本區(qū)別在于它變壓器不工作在工頻而是工作在幾十千赫茲到幾兆赫茲，功能管不是工作在飽和及截止區(qū)即開關(guān)狀態(tài)，開關(guān)電源因此而得名。開關(guān)電源的優(yōu)點(diǎn)是體積小，重量輕，穩(wěn)定可靠；缺點(diǎn)相對于線性電源來說紋波較大（一 般≤ 1% V )( PPo ? ，好的可做到十幾 mV PP? 或更小 )。它的功率可自幾瓦－幾千瓦均有產(chǎn)品。 1 STC12C5608AD 簡述 STC12C5608AD 系列單片機(jī)簡要介紹 STC12C5608AD /AD/PWM 系列單片機(jī)是宏晶科技生產(chǎn)的單時鐘 /機(jī)器周期 (1T)的單片機(jī)，是高速 /低功耗 /超 強(qiáng) 抗干擾的新一代 8051 單片機(jī)，指令代碼完全兼容傳統(tǒng) 8051,但速度快 812倍。內(nèi)部集成 MAX810 專用復(fù)位電路 ,2路 PWM,8 路高速 1