摘 要

電源是實現(xiàn)電能變換和功率傳遞的主要設(shè)備。在信息時代，農(nóng)業(yè)、能源、交通運輸、通信等領(lǐng)域迅猛發(fā)展，對電影產(chǎn)業(yè)提出個更多、更高的要求，如節(jié)能、節(jié)材、減重、環(huán)保、安全、可靠等。這就迫使電源工作者不斷的探索尋求各種鄉(xiāng)關(guān)技術(shù)，做出最好的電源產(chǎn)品，以滿足各行各業(yè)的要求。開關(guān)電源是一種新型的電源設(shè)備，較之于傳統(tǒng)的線性電源，其技術(shù)含量高、耗能低、使用方便，并取得了較好的經(jīng)濟效益。
UC3842是一種性能優(yōu)良的電流控制型脈寬調(diào)制器。假如由于某種原因使輸出電壓升高時，脈寬調(diào)制器就會改變驅(qū)動信號的脈沖寬度，亦即占空比D，使斬波后的平均值電壓下降，從而達到穩(wěn)壓目的，反之亦然。UC3842可以直接驅(qū)動MOS管、IGBT等，適合于制作20～80W小功率開關(guān)電源。由于器件設(shè)計巧妙，由主電源電壓直接啟動，構(gòu)成電路所需元件少，非常符合電路設(shè)計中“簡潔至上”的原則。設(shè)計思路，并附有詳細的電路圖。

關(guān)鍵詞：開關(guān)電源，uc3842，脈寬調(diào)制，功率，IGBT












SWITCHING POWER SUPPLY DESIGN BASED ON UC3842

ABSTRACAT


Power is to achieve power conversion and power transmission major equipment. In the information age, agriculture, energy, transportation, communications and other areas Power of the film industry make a greater and higher requirements，such as energy, materials, weight reduction, environmental protection, safety and reliability. This has forced the power workers have been exploring the technology for a variety of rural customs, the power to make the best products to meet the requirements of all walks of life. Switching power supply is a new type of power supply, compared to traditional linear power supply, high technology, low energy consumption, easy to use, and has achieved good economic results.
UC3842 is an excellent current-controlled pulse width modulator. If for some reason, the output voltage increases, the pulse width modulator drive signal will change the pulse width, that is, the duty cycle D, so that the average voltage drop after the chopper to achieve the regulator end, and vice versa how ever.UC3842 can control direct drive MOS, IGBT, etc., suitable for the production of 20 ~ 80W low-power switching power supply. As the device is cleverly designed, launched by the main power supply voltage directly to form circuit components required for a small, very consistent with circuit design, "simplicity first" principle.


KEY WORDS: Switching Power Supply，uc3842，PWM，power，IGBT

目　錄

前 言 1
第1章 開關(guān)電源的簡介 2
1.1 開關(guān)電源概述 2
1.1.1 開關(guān)電源的工作原理 2
1.1.2 開關(guān)電源的組成 3
1.1.3 開關(guān)電源的特點 4
1.2 開關(guān)器件 4
1.2.1開關(guān)器件的特征 4
1.2.2器件TL431. 5
1.2.3電力二極管 6
1.2.4光耦PC817 6
1.2.5電力場效應(yīng)晶體管MOSFET 7
第2章 主要開關(guān)變換電路 9
2.1 濾波電路 9
2.2 反饋電路 9
2.2.1電流反饋電路 9
2.2.2電壓反饋電路 10
2.3電壓保護電路 10
第3章 UC3842 12
3.1 UC3842簡介 12
3.1.1 UC3842的引腳及其功能 12
3.1.2 UC3842的內(nèi)部結(jié)構(gòu) 13
3.1.3 UC3842的使用特點 14
3.2 UC3842的典型應(yīng)用電路 15
3.2.1反激式開關(guān)電源 15
3.2.2 UC3842控制的同步整流電路 16
3.2.3升壓型開關(guān)電源 19
第4章 利用UC3842設(shè)計小功率電源 21
4.1 電源設(shè)計指標 21
4.1.1元件的選擇 21
4.1.2電路結(jié)構(gòu)的選擇 23
4.2 啟動電路 23
4.3 PWM脈沖控制驅(qū)動電路 24
4.4 直流輸出與反饋電路 25
4.5 總體電路圖分析 26
結(jié) 論 28
參考文獻 29
致 謝 30
附 錄1：總體電路圖 31
附 錄2：開關(guān)電源常用英文標志與縮寫 32
外文資料譯文 33