【正文】 M 對 LED 亮度進行調(diào)節(jié)， STC89C52作為主控芯片，設(shè)置了手動控制。在手動控制時，通過兩個按鍵輸出不同的 PWM 占空比對 LED的電流進行控制，從而實現(xiàn)了對光度的手動調(diào)節(jié)。 PWM調(diào)節(jié) LED 亮度 是一種利用簡單的數(shù)字脈沖反復(fù)開關(guān)白光 LED 驅(qū)動器的調(diào)光技 術(shù)。 不管用 Buck,Boost,BuckBoost 還是線性調(diào)節(jié)器來驅(qū)動 LED。一些應(yīng)用只是簡單地來實現(xiàn)“開”和“關(guān)”地功能 ， 但是更多地應(yīng)用需求是要 基本 從 0 到 100%調(diào)節(jié)光的亮度 。使用開關(guān)電路以相對于人眼識別力來說足夠高的頻率工作來改變光輸出的平均值 ，即數(shù)字調(diào)光 。 關(guān)鍵詞 單片機 ， 數(shù)字脈沖 ， 占空比 調(diào)節(jié) ， 驅(qū)動電路 ， LED 亮度調(diào)節(jié) ABSTRA Because C51SCM and PWM can regulate the brightness of the white light LED, STC89C5 as the DSP set up the manual control. During the process of the manual control, different PWM duty ratio output by two key regulate the electric current of LED so as to realize the manual control of the luminosity. As a matter of fact, C51SCM don’t have the interface. The control of the brightness of LED is realized by the software which simulating the situation that PWM adjust the duty ratio of the high level and the low level. PWM dimming is a technology which makes use of simple digital pulse so as to switch white LED drive repeatedly. For Buck, Boost, BuckBoost or linear regulation to drive LED, their mon ideas are using drive circuit to control the output of light. Some applications only achieve the “on” and “off” function simply. While more application demand that it can regulate the brightness of light from 0 to 100% and often have very high precision. Digital dimmer is the use of the switch circuit which works in a high frequency with respect to human recognition capacity to change the average of the light output. The use of pulse width modulation to set the cycle and duty ratio is probably the simplest method to realize digital dimming and Buck regulator topology can often provide the best performance. KEY WORDS: SCM, digital pulse, dutycycle correction, driver circuit, regulation of LED brightness 目 錄 前 言 ............................................................................................................................. 4 第 1章 單片機應(yīng)用技術(shù)簡介 ............................................................................................ 6 ............................................................................. 6 單片機內(nèi)部構(gòu)成 ................................................................................................... 9 第 2 章 PWM 調(diào)光原理簡介 ......................................................................................... 10 調(diào)節(jié) LED亮度原理 ................................................................................... 10 脈沖寬度調(diào)節(jié) .......................................................................................... 10 PWM對于 LED 調(diào)光的優(yōu)勢 ................................................................... 11 LED光源介紹 ................................................................................................. 13 LED燈簡介與顯示原理 ............................................................................ 13 光源的特性 ....................................................................................... 14 第 3 章 電路設(shè)計及功能模塊介紹 ................................................................................. 16 電 路設(shè)計流程圖 ................................................................................................. 16 功能模塊介紹 .................................................................................................... 16 按鍵功能設(shè)計 ........................................................................................... 16 BUCK 電路介紹 ....................................................................................... 16 A0832 芯片介紹 ........................................................................................ 19 電源的選擇 .............................................................................................. 21 四位數(shù)碼管介紹 ....................................................................................... 22 第 4 章 軟件系統(tǒng)的設(shè)計與仿真 ...................................................................................... 24 電路圖的設(shè)計仿真 ............................................................................................ 24 單片機軟件仿真系統(tǒng) Proteus 介紹： ......................................................... 24 Proteus 仿真電路圖 ................................................................................... 25 軟件設(shè)計及仿真 ................................................................................................ 26 Keil μVision2 開發(fā)環(huán)境介紹： ................................................................ 26 ............................................................................................... 28 單片機內(nèi)部程序的編寫 ...................................................................................... 29 第 5 章 實物裝配與調(diào)試 ............................................................................................... 30 實物裝配流程 .................................................................................................... 30 按照電路圖 （圖 422）焊接組件 ............................................................ 30 設(shè)計實物圖見（附錄一） ......................................................................... 30 試驗中的調(diào)試結(jié)果見（附錄二） ........................................................................ 30 5. 3 裝配與調(diào)試中的問題 ......................................................................................... 30 總 結(jié) ............................................................................................................................. 31 致 謝 ........................................................................................................................... 32 參考文獻 ........................................................................................................................ 33 附 錄 ........................................................................................