模電課程設(shè)計(jì)報(bào)告音頻放大器

1、 模擬電子技術(shù)課程設(shè)計(jì) 題目名稱：音頻功率放大器班級(jí)：電1005-1班姓名：2012年6月21日摘要：在現(xiàn)實(shí)生活中聲音信號(hào)非常重要，但有些信號(hào)非常小只有對(duì)其進(jìn)行放大后才能滿足我們的要求。音頻功率放大器的作用是將聲音源輸入的信號(hào)進(jìn)行放大，然后輸出驅(qū)動(dòng)揚(yáng)聲器。聲音源的種類很多，因此其輸出的信號(hào)的電壓差別很大，所以對(duì)功率放大器要求很高，同時(shí)也要能根據(jù)信號(hào)源的大小進(jìn)行調(diào)節(jié)，以防止輸入信號(hào)失真，同時(shí)在輸入信號(hào)小時(shí)也能保證其正常發(fā)揮作用。目錄1摘要·············&#

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15、183;·····························63正文3. 1系統(tǒng)設(shè)計(jì)方案 音頻功率放大器實(shí)現(xiàn)對(duì)音頻的放大,電路中通過(guò)滑動(dòng)變阻器實(shí)現(xiàn)對(duì)音量的調(diào)節(jié)，通過(guò)濾波電容來(lái)實(shí)現(xiàn)對(duì)信號(hào)的濾波，通過(guò)TDA2030來(lái)實(shí)現(xiàn)對(duì)音頻的放大，通過(guò)負(fù)反饋來(lái)減小信號(hào)的放大失真。3. 1.1電路框圖 電聲轉(zhuǎn)換器音頻放大聲

16、電轉(zhuǎn)換器 3.1.2總體電路圖3.2單元電路設(shè)計(jì)及參數(shù)的選擇3.2.1調(diào)頻模塊本電路中,通過(guò)滑動(dòng)變阻器（22k）來(lái)改變信號(hào)輸入的大小,從而實(shí)現(xiàn)對(duì)輸出聲音大小的調(diào)節(jié)。同時(shí)如果調(diào)整圖中150K、4.7K電阻的“比值”，可以改變“負(fù)反饋”的大小。而負(fù)反饋的大、小，對(duì)輸出波形有改善作用，也會(huì)明顯改變輸出音量的。3.2.2濾波電路模塊22uF是將由電源經(jīng)兩個(gè)100K電阻分壓后的電壓進(jìn)行濾波(去耦)后，再經(jīng)100K電阻給TDA2030的1腳提供工作點(diǎn)。有隔直流作用，并提供交流通路。3.2.3負(fù)反饋模塊4.7K與150K電阻分壓后提供負(fù)反饋信號(hào)，用以改善音質(zhì)，和調(diào)整輸出電平的。反饋系數(shù)F約是4.7/(150

17、+4.7)=0.03，故放大器的電壓放大倍數(shù)約是1/F，即33左右。如果沒(méi)有這個(gè)22，2腳直流電壓就經(jīng)4.7K接地了。3.2.4音頻放大模塊本電路音頻放大選的為T(mén)DA2030此運(yùn)放具有以下特點(diǎn)1、外接元件非常少。2、輸出功率大，Po=18W(RL=4)， Po=16W(RL=8， ±19V)。3、采用超小型封裝（TO-220）,可提高組裝密度。4、內(nèi)含各種保護(hù)電路，因此工作安全可靠。主要保護(hù)電路有：短路保護(hù)、熱保護(hù)、地線偶然開(kāi)路、電源極性反接（Vsmax=12V）以及負(fù)載泄放電壓反沖等。5、TDA2030A能在最低±6V最高±22V的電壓下工作。3.3改進(jìn)方案如果輸入信號(hào)過(guò)小可以考慮增加前置放大電路，同時(shí)可以考慮在信號(hào)輸入端增加個(gè)濾波電容，以便消除信號(hào)干擾。4總結(jié)在本次課程設(shè)計(jì)