【正文】 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文 I 畢業(yè)設(shè)計(jì) _車載章頻功率放大器設(shè)計(jì) 摘 要 電子信息技術(shù)幾乎主宰了整個(gè)電器行業(yè)的發(fā)展，隨著電子技術(shù)的進(jìn)步發(fā)展在功率放大器的設(shè)計(jì)上功能也不斷更新。功率放大器在家電、數(shù)碼產(chǎn)品中的應(yīng)用也越來越廣泛，與我們?nèi)粘Ｉ钣兄芮嘘P(guān)系。隨著生活水平的提高，人們越來越注重視 覺，音質(zhì)的享受。在大多數(shù)情況下，增強(qiáng)系統(tǒng)性能，如更好的聲音效果 ,是促使消費(fèi)者購買產(chǎn)品的一個(gè)重要因素。音頻功率放大器作為音響等電子設(shè)備的后級放大電路，它的主要作用是將前級的音頻信號進(jìn)行功率放大以推動負(fù)載 工作，獲得良好的聲音效果。同時(shí)音頻功率放大器又是音響等電聲設(shè)備消耗電源能量的主要部分。 目前，音頻功率放大器仍以模擬功放為主流產(chǎn)品，模擬功放經(jīng)歷了數(shù)十年的不斷改進(jìn)和完善，其技術(shù)已發(fā)展到了頂峰。模擬類功放是以線性放大為基礎(chǔ)，功率放大器件有電子管和晶體管兩類。按功放靜態(tài)工作點(diǎn)的設(shè)置可分為Ａ類放大，Ａ /Ｂ類放大和 C類放大三種。晶體管功放的最大優(yōu)點(diǎn)是電源轉(zhuǎn)換效率高（ C類功放最大可達(dá) 55%）、體積小、重量輕、發(fā)熱量不大、生產(chǎn)成本低。缺點(diǎn)是轉(zhuǎn)換速率低、偶次諧波失真較大。音質(zhì)和可靠性指標(biāo)都略遜于電子管功放。隨著晶體管制 造技術(shù)的不斷提高和新技術(shù)的應(yīng)用，各項(xiàng)實(shí)用性指標(biāo)和可靠性指標(biāo)都有很大改善，并不斷在向更大的輸出功率、更小的體積、更輕的重量、更多的功能和智能化方向發(fā)展。 本文介紹了音頻功率放大器構(gòu)成、功能、及工作原理等。音頻功率放大器從電路從結(jié)構(gòu)上來分有， OTL， OCL， BTL。采用 LM1875 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文 II 和 TDA1521 放大是構(gòu)成本產(chǎn)品主要部件，接下來將設(shè)計(jì)方案原理制成 PCB 板，通過原理圖及所要元件焊接電路板，在對電路板進(jìn)行測試最終完成設(shè)計(jì)任務(wù)。 關(guān)鍵詞： LM1875 功率芯片 音頻功率放大器 PCB 車載 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文 III Abstract Electronic information technology has dominated the appliance industry is almost the development of electronic technology, with the development of the design in power amplifier functions are constantly updated. Power amplifier, digital products in home appliance and more extensive application, and our daily life is closely. As standard of living rise, people pay more and more attention to visual and audio enjoyment. In most cases, enhance the system performance, such as sound effect, it is better to consumers to buy the product is one of important factors. Audio power amplifier as acoustics electronic equipment level amplifier circuit after, its main function is to the audio signal before class to promote the work load power amplifier, obtain good effect. While audio amplifier is acoustics acoustic equipment, the main part of the power consumption. At present, audio amplifier with analog amplifier is still the mainstream products, experienced decades of amplifier improvement continuously, the technology has already developed into peak. Such amplifier is simulated based on linear amplification, power amplifier device has tubes and two classes. Transistor According to the set point static amplifier can be divided into A kind of amplifier, 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文 IV A/B class C amplifier amplification and three. The biggest advantage is the transistor amplifier power conversion efficiency (C amplifier can 55%), small volume, light weight, low calorific value, production cost. Conversion rate is low, the shorting is harmonic distortion. Quality and reliability indexes are slightly inferior tube amplifiers. With the improvement of transistor manufacturing technology and the application of new technology, and the practicability and reliability indexes are greatly improved index, and constantly to more power output, smaller, lighter weight, volume, and more functions and intelligent direction. The paper introduces the audio power amplifier structure, functions, and the work principle, etc. Audio amplifier circuit structure from up from there, OTL, OCL portion, BTL. Using LM1875 and TDA1521 amplifier is the main ponent that constitute the product design scheme, PCB principle diagram and wanted by welding circuit, in the ponent circuit design test finally。 Keywords: LM1875 power chips audio amplifier PCB vehicle 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文 V 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文 i 目 錄 前 言 ............................................................. 1 第一章 概 述 ..................................................... 2 1． 1 音響的相關(guān)知識簡介 ........................................... 2 聲音的基本特性嗍 ......................................... 3 音響的結(jié)構(gòu)及參數(shù) ......................................... 3 放大器技術(shù)指標(biāo) ........................................... 3 音頻放大器分類 ............................................... 4 A 類（甲類）放大器 ....................................... 5 B 類（乙類）放大器 ....................................... 6 AB 類（甲乙類）放大器 .................................... 7 D 類（丁類）放大器 ....................................... 8 AB 類放大器與 D 類放大器效率比較 ......................... 9 總結(jié) ................................................... 10 第二章 車載功率放大器的設(shè)計(jì) ...................................... 12 設(shè)計(jì)要求 ： ................................................... 12 設(shè)計(jì)過程 ..................................................... 12 擬定總體方案： ........................................... 12 單元電路的設(shè)計(jì) ............................................... 14 前置放大級 ............................................... 14 音調(diào)控制級 ............................................... 16 第三章 核心元器件的介紹 .......................................... 25 LM1875 的參數(shù)簡介 ............................................ 25 LM1875 的工作原理： ......................................... 25 河南理工大學(xué)萬方科技學(xué)院本科畢業(yè)論文 ii LM1875 的電路特點(diǎn) ........................................... 26 第四章 電路設(shè)計(jì) ................................................. 28 穩(wěn)壓電源的設(shè)計(jì) .............................................. 28 典型應(yīng)用電路 ................................................. 29 雙電源功率放大器原理圖 ....................................... 31 雙電源音頻功率放大器 PCB 圖 ................................... 32 第五章 PCB 的制作 ................................................. 33 對元器件的前期準(zhǔn)備 ........................................... 33 Sch 原理圖應(yīng)注意常見問題 ..................................... 3