【正文】 4 LM2576為核心，其中固定輸出部分分別為177。 5V、177。 關(guān)鍵詞 : 開關(guān)電源；穩(wěn)壓； 51MCU； A/D； D/A II ABSTRACT The design of the switching power supply from the pulse width modulator (PWM) and bipolar transistor structure, introduced the AT89C51 microcontroller based digital control of adjustable switching power supply, system UC3842, LM2576 as the core, some of which were fixed output 177。 15V, adjustable to control in part by highperformance microcontroller core, by adjusting the LM2576ADJside, to achieve the digital output voltage adjustable, the input mode with the keyboard, the output voltage with LCD display, to achieve targets ripple factor Um ≤ 5mU, stability △ V0 / V0 100% ≤ 1%, step , the system has good stability, high accuracy, low cost, high efficiency, its performance is far superior to the traditional linear adjustable power supply, greatly improved the performance of traditional power supply, easy to use, suited for general use in teaching and research. Keyword: switching power supply； regulators； 51MCU； A/D； D/A 智能穩(wěn)壓電源設(shè)計(jì) 目 錄 摘 要 .............................................................................................................................I ABSTRACT.................................................................................................................. II 第一章 前言 .................................................................................................................. 1 研究的目的和意義 ......................................................................................... 1 穩(wěn)壓電源的分類 ............................................................................................. 1 線性電源分類 ........................................................................................ 2 開關(guān)電源的分類 .................................................................................... 2 穩(wěn)壓電源的主要指標(biāo) ..................................................................................... 3 特性指標(biāo) .............................................................................................. 3 技術(shù)指標(biāo) .............................................................................................. 4 穩(wěn)壓電源的發(fā)展 .............................................................................................. 5 研究主要內(nèi)容 ................................................................................................. 7 第二章 開關(guān)穩(wěn)壓電源的原理 ...................................................................................... 8 開關(guān)穩(wěn)壓電源的工作原理 ............................................................................. 8 開關(guān)式穩(wěn)壓電源的基本原理框圖 ....................................................... 8 開關(guān)電源的控制方式 ........................................................................... 8 開關(guān)電源常見電路 ......................................................................................... 9 開關(guān)電源器件 ............................................................................................... 12 開關(guān)晶體管 ......................................................................................... 12 PWM 控制器 ........................................................................................ 13 第三章 智能穩(wěn)壓電源的硬件設(shè)計(jì) ............................................................................ 15 穩(wěn)壓電源方案論證 ....................................................................................... 15 系統(tǒng)工作原理 ............................................................................................... 15 整流濾波電路 ............................................................................................... 16 PWM 控制電路 ................................................................................................ 17 PWM 控制電路設(shè)計(jì) ............................................................................ 17 UC3842 簡(jiǎn)介 ....................................................................................... 19 穩(wěn)壓輸出電路 ............................................................................................... 21 . 穩(wěn)壓輸出電路設(shè)計(jì) ............................................................................ 21 LM2576 開關(guān)穩(wěn)壓集成電路 ............................................................... 22 可調(diào)輸出電路 ............................................................................................... 23 可調(diào)輸出電路設(shè)計(jì) ............................................................................ 23 運(yùn)算放大器 LM358........................................................................... 24 DAC0832 模塊電路 ............................................................................. 25 MCU 控制電路 ................................................................................................ 26 MCU 控制電路設(shè)計(jì) ............................................................................. 26 AT89C51 簡(jiǎn)介 ..................................................................................... 27 鎖存器 74LS573.................................................................................. 29 AD 轉(zhuǎn)換電路 .................................................................................................. 29 AD 轉(zhuǎn)換電路設(shè)計(jì) ............................................................................... 29 AD 轉(zhuǎn)換電路原理 ............................................................................... 29 LCD 液晶顯示電路 ........................................................................................ 30 LCD 液晶顯示電路設(shè)計(jì) ..................................................................... 31 按鍵電路設(shè)計(jì) ............................................................................................. 32 鍵盤原理 .......................................................................................... 32 鍵盤與單片機(jī)接口電路 .................................................................. 32 第四章 系統(tǒng)軟件設(shè)計(jì) ................................................................................................ 34 主