【正文】 在一定范圍內(nèi)與電流成正比， LED 的模擬調(diào)光是對(duì) LED 的每個(gè)周期進(jìn)行調(diào)整，簡(jiǎn)單地說(shuō)，它是不斷調(diào)整 LED 的電流大小來(lái)改變亮度的，可以通過(guò)調(diào)整電流檢測(cè)電阻 RSNS，或用模擬電壓驅(qū)動(dòng) IC 的某個(gè)調(diào)光功能引腳來(lái)完成。 關(guān)鍵詞 數(shù)字脈沖 /占空比 /驅(qū) 動(dòng)電路 /線性調(diào)節(jié) 基于單片機(jī)的 PWM 調(diào)光 II Based on SCM PWM dimming the lights ABSTRACT PWM dimming is a simple digital pulse, the repeated switching of white LED driver dimming technology. Application of the system only needs to provide a wide, narrow different digital pulse, can easily change the output current, thereby regulating the brightness of white light LED. PWM dimming has the advantage of being able to provide high quality white light, and the application of simple, high efficiency! For example, in a mobile phone system, using a special PWM interface can easily generate arbitrary duty cycle of the pulse signal, the signal is passed through a resistor, connected to the drive EN interface. Most manufacturers drive support PWM dimming. For Buck, Boost, BuckBoost or linear regulator to drive LED, their mon ideas are the drive circuit to control the output of light. Some applied simply to achieve the on and off function, but more application demand is to be from 0 to 100% regulates the brightness of the light, and often have very high precision. The designer has two main options: linear regulator LED current ( analog dimming ), or using the switch circuit with respect to human recognition capacity, a high enough frequency to change the average light output ( digital dimming ). The use of pulse width modulation ( PWM ) to set the cycle and duty cycle ( Figure 1 ) is probably the most simple digital dimming method, and Buck regulator topology can often provide a best performance. KEY WORDS digital pulse ,duty ,drive circuit ,linear regulator 基于單片機(jī)的 PWM 調(diào)光 III 目 錄 中文摘要 ……………………………………………………………………………………… I 英文摘要 ……………………………………………………………………………………… II 引 言 .......................................................................................................................... 1 1 單片 機(jī)應(yīng)用技術(shù)簡(jiǎn)介 ......................................................................................... 2 單片機(jī)內(nèi)部構(gòu)成 ....................................................................................... 2 單片機(jī)的工作原理 .................................................................................. 2 2 PWM 調(diào)光原理簡(jiǎn)介 ............................................................................................... 4 PWM 調(diào)光技術(shù)原理 ................................................................................... 4 脈沖寬度調(diào)節(jié) ...................................................................................... 4 PWM 對(duì)于 LED 調(diào)光的優(yōu)勢(shì) ................................................................... 5 LED 光源的特性 ........................................................................................ 7 3 電路設(shè)計(jì) ................................................................................................................ 8 電路設(shè)計(jì)流程圖 ....................................................................................... 8 主控元件與功能模塊介紹 .................................................................... 8 按鍵功能設(shè)計(jì) ...................................................................................... 8 主控元件單片機(jī) .................................................................................. 8 光源模塊 .............................................................................................11 電源的選擇與連接 .............................................................................11 其他元件工作特性 ................................................................................ 12 LED 發(fā)光二極管功能簡(jiǎn)介 ................................................................. 12 晶振的作用與電路的連接 ................................................................ 13 4 實(shí)物裝配與調(diào)試 ................................................................................................ 16 實(shí)物裝配流程 ......................................................................................... 16 按照電路原理圖焊接組件 ................................................................ 16 元器件清單及型號(hào) ............................................................................ 16 單片機(jī)內(nèi)部程序的編寫 ....................................................................... 16 焊接工序注意事項(xiàng) ................................................................................ 16基于單片機(jī)的 PWM 調(diào)光 IV 調(diào)試完善功能 ......................................................................................... 19 結(jié)束語(yǔ) ........................................................................................................................ 19 致 謝 .............................................................................................. 錯(cuò)誤 !未定義書簽。 不管用 Buck, Boost, BuckBoost還是