<div class="document"> <h3 class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;">1、项目功能介绍</h3> <hr class="horizontal-splitline normal-bold-2"> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;">个性功放:</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;">初学，0基础，只要能出声就行。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;">我想把蓝牙耳机输出的音频用"个性功放"进行放大，用喇叭放出来。同时还可以插普通有线耳机回放。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;"> </p> <h3 class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;">2、项目属性</h3> <hr class="horizontal-splitline normal-bold-2"> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;"><span style="color: #000000; font-size: 14px; background-color: #ffffff;">此项目是首次公开，也是我本人原创。纯属个人爱好，画着玩的。</span></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;"> </p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;"> </p> <h3 class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;">3、开源协议</h3> <hr class="horizontal-splitline normal-bold-2"> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;"><span style="color: #000000; font-size: 14px;">GPL3.0开源协议，未经许可不可商用。</span></p> <p> </p> <h3 class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;"> </h3> <h3 class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;">4、硬件部分</h3> <hr class="horizontal-splitline normal-bold-2"> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"> </p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><strong>4.1 芯片选用：</strong></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">前级功放采用TDA1308，这颗芯片我自己有，我下单的时候商城上没有库存。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">后级采用PAM8407，是看立创的莫工讲解时用的芯片，简单，功率不小，适合我。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"> </p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><strong>4.2 电路组成：</strong></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><strong>4.2.1 电源电路</strong></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">我选的是LM317，商城上选的。我是想用12V的适配器，用LM317变压到5V，给芯片供电。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">因为有些适配器的电源极性有的1脚是正极，有的是负极，为了防反接，我这里用了一个NMOS管，效果还不错。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">此电路输出电压大概在5.6V，电压比我预想的高了，在芯片的工作电压范围，就这样吧。我是按LM317的数据手册上的电路搭的，怎么会高出0.6V呢？是不是我的R9（5K）和R10（15K）选择有问题，有知道的吗，指点我一下，谢谢。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><br><img src="//image.lceda.cn/pullimage/Q8Ywkf4LQJd1SpEt5EN2Fiq7ExnfCzFvx9mG8uUT.png" alt="" width="566" height="263"></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><strong>4.2.</strong><strong>2 耳机功放</strong></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">我选的是TDA1308，电路也是完全按数据手册上的电路搭的，声音还可以。因为没有大阻抗的耳机，不知道推力有没有提升。PS：R5和R6这两个电阻是不是可以调节放大倍数？</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">这个电路一次成功，没有改动。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><img src="//image.lceda.cn/pullimage/Z8hhdn4JhtkGPsA685sVVpexP43o4y5BQym1p3AN.png" alt="" width="733" height="397"></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><strong>4.2.</strong><strong>3 喇叭功放</strong></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">PAM8407的引脚比较少，接线也简单，比较适合我这种第一次画PCB的初学者。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">这张图是我改过的，打样的PCB和这个是不一样的，14脚和11脚被我直接接地了，结果喇叭没有声音。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><img src="//image.lceda.cn/pullimage/7tQL7WshgULdebyNeYJZws6DqH6Ka2UiS8zikiGB.png" alt="" width="455" height="228"></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">线路画错，没办法，只好飞线。飞好线，声音出来了。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><img src="//image.lceda.cn/pullimage/D6dPuHCSRhUp25avktjjWV5qn0rexe93wAUPjVbq.png" alt="" width="1000" height="741"></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">PS：我的音频输入插座的线也被我画反了，左右声道反接了。因为凭记忆画的，没认为这个也会画错，就没检查。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">强迫症犯了，必须飞线解决。飞好的照片忘记拍了，这张照片是半成品。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><img src="//image.lceda.cn/pullimage/JMybuH35AjXoLU8CuFwNfwES4X2aC5WRqRuIZOAS.png" alt="" width="1000" height="650"></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">还有，本来我是想接一个音频插座，用来输出给耳机的，一开始失败了。因为只要已插入耳机，电源输出电流就陡增，接近短路，怎么会这样？插入耳机仅仅是断开了从TDA1308出来的信号而已，为什么电流会陡增，没搞清楚。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">后来发现喇叭在刚接通电源时，振膜鼓起来，这时电流表指针跳变不正常，大电流。估计就是喇叭线路的问题。我的电路是按莫工直播时教的电路做的，按道理不应该错啊，但看电流确实是不正常。既然是喇叭这里问题，振膜鼓起，估计是有直流电过来，莫工的电路里没有电容串到喇叭上，于是我在喇叭的接线柱上焊了100uF的电容（见下图），奇迹出现了，电流不大了，插入耳机电流也不陡增了。到此，我想实现的功能都做到了，激动。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">（PS:已将PAM8407第二脚和第七脚串联0.1uF的电容，电路图已改正）</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><img src="//image.lceda.cn/pullimage/XgZzKDd2LsYKHIQFlOHq8h4XvvHi0omCDL9mN1ql.png" alt="" width="1000" height="579"></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><strong>4.2.</strong><strong>4 蓝牙输入</strong></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">输入这块我预留了蓝牙耳机输入的焊盘，这样就不用单独设计蓝牙模块，直接把旧的蓝牙耳机拆下电路板，接接线就能实现蓝牙无线播放了。</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><img src="//image.lceda.cn/pullimage/NYIpwlfryjVyJxat8GhxOdTqqPQZ1yhdzCnIf0vw.png" alt="" width="1000" height="478"></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><strong>4.3 </strong><strong>最后成品展示：</strong></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;">飞线有点丑，图纸已经改了<strong>。</strong></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"><img src="//image.lceda.cn/pullimage/dY2UTjPK1RCSqO3es0Sxsp1bXoAXMKZUtX2ohzGu.png" alt="" width="1000" height="632"></p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt pap-left-indent-1.6em" style="line-height: 1.8;"> </p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;"> </p> <h3 class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;">5、演示视频</h3> <hr class="horizontal-splitline normal-bold-2"> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;"> </p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;">请看视频</p> <p class="paragraph text-align-type-left pap-line-1.3 pap-line-rule-auto pap-spacing-before-3pt pap-spacing-after-3pt" style="line-height: 1.8;"> </p> </div>