l14107cb 发表于 2024-10-10 05:25:28

电源芯片大盘点！选型攻略？经典VS新兴哪个好


    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">科技日新月异，各大半导体<span style="color: black;">机构</span>推出了成千上万的芯片，原来经典的芯片还<span style="color: black;">拥有</span>领先性吗？</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">今天从实战<span style="color: black;">处理</span>问题的<span style="color: black;">方向</span>出发，对比经典电源芯片与新兴的电源芯片的异同，以及教<span style="color: black;">大众</span><span style="color: black;">怎样</span>基于真实的<span style="color: black;">需要</span>完成器件选型，开启板级电源的设计。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">器件选型<span style="color: black;">触及</span>到非常多的考量<span style="color: black;">原因</span>，虽然<span style="color: black;">大众</span>都<span style="color: black;">已然</span>学习了<span style="color: black;">区别</span>的电源的拓扑结构，但当真正做设计的时候，到底选哪个芯片，还是无从下手。有可能就找一个过去用过的，用得顺手的<span style="color: black;">或</span>找同事<span style="color: black;">或</span>是<span style="color: black;">机构</span>以前用过的简单芯片，快速拿过来就用。但<span style="color: black;">大众</span>有想过吗，有可能你<span style="color: black;">选取</span>的这个器件真的不<span style="color: black;">必定</span>匹配和适合新的设计。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">因此</span>接下来，老师带领<span style="color: black;">大众</span>思考板级电源的设计及选型问题。下面就挑选了大部分工程师在设计中会用到的四大类芯片：<strong style="color: blue;">Reference 电压基准、LDO、降压Buck电路与升压Boost电路</strong>。这四大类别基本上<span style="color: black;">包括</span>了板级电源设计<span style="color: black;">其中</span>90%以上的电源<span style="color: black;">需要</span>。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">每一个</span>电源需要考量<span style="color: black;">非常多</span><span style="color: black;">区别</span>的参数指标：</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/3df55d7818d04c6bbf18539a89a323ae~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=BJhU40p7sAZbWXbN8pIDUwKKobs%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">例如</span>开篇讲过的LDO 在设计时，就要<span style="color: black;">思虑</span>到输出电流、最小压差、<span style="color: black;">实质</span>工况、封装热阻、低噪声、瞬态响应、静态电流等等。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">而Buck和Boost则要<span style="color: black;">思虑</span>输入/输出电压、输出电流的能力、开关频率、转换效率、瞬态响应、静态电流、纹波和EMI等等。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">同期</span>Buck和Boost还有两个参数指标要单独<span style="color: black;">思虑</span>，Buck电路的最大占空比，Boost电路的输出隔离。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">大众</span>看到的Buck电路和Boost电路用的最多的都是集成MOS管、电感外置的。什么<span style="color: black;">状况</span>下需要用来Controller，用外置的MOS管呢？<span style="color: black;">此刻</span>比较流行的全集成模块到底有什么优点，什么缺点？下面将会一一解答。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">1</span></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">Reference 电压基准</strong></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">电压基准在板上的应用，<span style="color: black;">非常多</span>人不会<span style="color: black;">留意</span>。在讲LDO的时候，<span style="color: black;">咱们</span><span style="color: black;">亦</span>提醒过<span style="color: black;">大众</span>，<span style="color: black;">千万不要用LDO去代替Reference</span>。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">在信号链路中，<span style="color: black;">为何</span>要用Reference电压基准呢？<span style="color: black;">由于</span>在ADC和DAC的电路<span style="color: black;">其中</span>，都需要有一个<span style="color: black;">能够</span>用来做比较的、<span style="color: black;">精细</span>的、稳定的、<span style="color: black;">靠谱</span>的、低噪声的、<span style="color: black;">期盼</span>它恒定不变的电压源<span style="color: black;">做为</span>基准。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/5521ef8c0e584c5fa16311a8af58d847~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=IR7BgmQpUlMQ5azeKM6HqwZC%2BHA%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">基准是有专门的芯片的，从结构上来讲分为两大类：</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/cc0f0167779a4f96878950f6bf956e22~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=lgHDWzQX7DSV9U1p1EsoTdVFmtg%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">一类是并联型<span style="color: black;">或</span>分流型电压基准；一类是串联型的电压基准，<span style="color: black;">一般</span>有三个脚，给它加一个电压，<span style="color: black;">而后</span>它的<span style="color: black;">另一</span>一个脚就是输出一个稳定的基准，<span style="color: black;">咱们</span>叫串联型的电压基准。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">在选型时，</span>基准电压有什么参数指标要去<span style="color: black;">思虑</span>？</strong><span style="color: black;">低噪声、初始电压精度 温度稳定性、<span style="color: black;">长时间</span>漂移</span>。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">第1</span>个，<span style="color: black;">为何</span>噪声如此重要</strong>？以ADC采样为例，<span style="color: black;">倘若</span><span style="color: black;">咱们</span>用ADC对信号做采样。假如基准是3.3V，那这个ADC采样的最小分度是多少呢？<span style="color: black;">倘若</span>是12位ADC，最小分度是0.8mV，以此类推，<span style="color: black;">倘若</span>是20bit的ADC的时，就需要3μV的最小分度，24bit则是0.2μV。这就<span style="color: black;">寓意</span>着基准电压上面的纹波噪声<span style="color: black;">不可</span>超出了最小分度，否则ADC就没法比较，换句话说看不到真实的信号。<span style="color: black;">因此</span>基准电源的噪声尤为重要。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/2e523e9bac2743b89a21aa728ae6c11b~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=LxLgworMrIHSdTBwuZf1ZxcK0Qk%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">在基准电压芯片的数据手册中，有这几项：</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/9a8a7db61b684e1998e173768f08cfc3~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=R2lv7mSrz%2BUCcDx%2F%2Br0kqeimzRg%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">为何</span><span style="color: black;">不可</span>用LDO做基准，<span style="color: black;">由于</span>LDO的初始精度<span style="color: black;">一般</span>是1%或2%，3.3V并不是3.3V。但<span style="color: black;">倘若</span>用基准芯片，标<span style="color: black;">叫作</span>的是±0.025%，<span style="color: black;">寓意</span>着上电之后2.5V的基准，输出的电压值足够<span style="color: black;">精细</span>，<span style="color: black;">便是</span>±0.025<span style="color: black;">%</span>这个误差范围之内，非常非常<span style="color: black;">精细</span>。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">第二，温度稳定性<span style="color: black;">为何</span>重要？</strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">在这个表格里面<span style="color: black;">便是</span>Low Dritt，<span style="color: black;">便是</span>当温度每变化一度，基准的电压就会<span style="color: black;">出现</span>偏移。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p26-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/25c9dba664c540ad97cd79448f9b7a64~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=q89OWEhq3Mk1%2BUXxux3J0Ch0S1g%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">例如</span>2.5V电压偏移多少，每一度百万分之二这个参数值，<span style="color: black;">亦</span>是远远好于LDO的。温度稳定性决定了电路在<span style="color: black;">区别</span>的工作环境下，它的基准会不会漂移。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">第三个，<span style="color: black;">长时间</span>漂移是什么？</strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">便是</span>上电用了一段时间之后，电压会慢慢地漂，但漂得很小。那这个<span style="color: black;">长时间</span>漂移<span style="color: black;">咱们</span>叫Long Term Drift，<span style="color: black;">便是</span>上图中的第三个参数。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">还有一个参数<span style="color: black;">便是</span>静态电流，在工业设备上<span style="color: black;">道理</span>不大，但在手持设备<span style="color: black;">或</span>是需要<span style="color: black;">长时间</span>稳定工作的<span style="color: black;">精细</span>采样设备中，静态电流就比较重要了。所有的这个基准的芯片在规格书里面都会给出这个Operation current，会看到<span style="color: black;">例如</span>说LT1389800nA 就0.8μA，<span style="color: black;">而后</span>REF3325 3312 339 各不<span style="color: black;">同样</span>，其实<span style="color: black;">已然</span>很低了。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/3aa5a5edf02147b19b157160ac90d896~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=vTd2T9W%2BfWcPkdDVmSTt69lA%2BUI%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">电压基准的设计选型<span style="color: black;">其中</span>的<span style="color: black;">有些</span><span style="color: black;">需求</span>和<span style="color: black;">重视</span>事项：<span style="color: black;">第1</span>点是<span style="color: black;">选取</span>基准的时候，<span style="color: black;">首要</span>要判断ADC<span style="color: black;">或</span>是所需要的最小分度和精度是多少位的<span style="color: black;">或</span>DAC这个精度要多少；第二点是要<span style="color: black;">思虑</span>的工作环境、温度稳定性，要去算这个误差会不会在范围之内。只要噪声、初始精度和稳定性都能搞定，基本上<span style="color: black;">便是</span>一个符合<span style="color: black;">需求</span>的基准电压芯片。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">2</span></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">LDO电源设计选型要点</strong></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">为何</span>用LDO而不是用DC-DC？<span style="color: black;">由于</span>LDO简单，三个脚，一正一负一输出。<span style="color: black;">然则</span>LDO是有潜在<span style="color: black;">危害</span>的，用LDO的时候要<span style="color: black;">思虑</span>以下参数：输出的电流能力、最小压差、封装的热阻。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">大众</span>用LDO的时候，<span style="color: black;">必定</span><span style="color: black;">想要</span>方设法地降低工况的压差，有两个参数指标，一个叫芯片的最小压差，<span style="color: black;">便是</span>输入端电压必须要比输出端要高。有些芯片可能<span style="color: black;">仅有</span>30mV或40mV，而有的需要0.6V。<span style="color: black;">倘若</span><span style="color: black;">能够</span><span style="color: black;">选取</span>最小的压差的芯片，<span style="color: black;">况且</span>去<span style="color: black;">调节</span>工况，就<span style="color: black;">能够</span><span style="color: black;">极重</span>的优化LDO的效率。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">举个例子，板子需要一个1.8V的电压，从2.5V转1.8V和从5V转1.8V，效率、损失和发热，差的不是一倍两倍。<span style="color: black;">因此</span>想用最小压差的芯片，就尽可能去找跟需要的输出电压最接近的那个电压的LDO。<span style="color: black;">倘若</span>电流<span style="color: black;">尤其</span>大，5A、10A，<span style="color: black;">此时</span><span style="color: black;">一般</span>就不<span style="color: black;">意见</span>用LDO，会发热严重。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">另一</span>LDO的噪声<span style="color: black;">亦</span>非常重要，LT1763-3.3这个输出的噪声大概是可能几十个μV，比开关电源要小<span style="color: black;">非常多</span>。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ade168278f204af0b52b2a81ac459507~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=pcaIP2JmJMmBrOSDsUOKiv0FpoM%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">在时钟<span style="color: black;">或</span>射频、微波的电路中，LDO<span style="color: black;">能够</span>做一个非常纯粹的电源。<span style="color: black;">尤其</span>是做无线通讯的时候，<span style="color: black;">这儿</span>面就有一个很重要的参数指标，PSRR输入输出的噪声<span style="color: black;">控制</span>比。dB值越高说明LDO的纹波和噪声的<span style="color: black;">控制</span>能力就越强。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/e90932ed0f8e4d6b95ab33708d1eeb8c~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=AzLTLxsPRktZ4hlF9G8jzL9xGEA%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">业界两大<span style="color: black;">机构</span>ADI 和TI的超低噪声到底能流到什么水平？</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">倘若</span>看RMS噪声，ADI有一系列的<span style="color: black;">制品</span>的RMS的噪声<span style="color: black;">仅有</span>0.8uV，TI有一个器件器件有0.46uV，真的是超低噪声。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/9ff9e19f8e4549a6b5b85393d86b1516~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=MlP5%2FGQ8hUZlG2i5lgyua23%2FeAI%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">LDO不仅看RMS的噪声，还要看它的噪声<span style="color: black;">控制</span>比，每家各有所长。TI最牛的最低噪声LDO，它的PSRR值大概78个dB。<span style="color: black;">然则</span>ADI的最高竟然<span style="color: black;">能够</span>高到117dB，简直真的是逆天了。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/cd2dcf83c4b9431f9d8befbbb4eb9a7b~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=7C2WkxqgjqozoCJf8js4FJeokoQ%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">从噪声和PSRR值来讲，这<span style="color: black;">表率</span>了行业里面比较顶尖的水平。当<span style="color: black;">而后</span>面还应该会有越来越多的<span style="color: black;">机构</span>挑战这个极限，推高PSRR和降低RMS的Noise。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">倘若</span>你做微波射频、高精度采样，那这个电源<span style="color: black;">必定</span>是需要选超低噪声的LDO的，但<span style="color: black;">倘若</span>是普通的数字电路那无<span style="color: black;">所说</span>了，1117就<span style="color: black;">能够</span>。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">关于<span style="color: black;">区别</span>厂家的1117芯片对比以及瞬态响应复盘，在视频中有<span style="color: black;">仔细</span>的讲解，<span style="color: black;">能够</span>拉至22:00分学习，<span style="color: black;">这儿</span><span style="color: black;">再也不</span>介绍了。</strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">3</span></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">开关电源设计选型要点</strong></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">经典的未必永恒。LM2596电路，相信很多工程师对这个电路<span style="color: black;">熟练</span>的<span style="color: black;">不可</span>再<span style="color: black;">熟练</span>。有人拿LM2596做简单的电源模块，<span style="color: black;">然则</span>这个经典的电路真的很好吗？</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/a7d967a313ef4eb799c996f0cad4117b~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=nklbPiBE0ysbSCEMtMS%2Bs7GCHdc%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">LM2596<span style="color: black;">已然</span>用了二三十年了，<span style="color: black;">此刻</span><span style="color: black;">亦</span>出了新的芯片LM53603，还有ADI的LT8641，<span style="color: black;">各样</span>各样的芯片。这些芯片的区别在哪里呢？</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/d087422d49694e8ba1497da78daf95c1~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=b1%2F0xzRygmyR5B%2F%2Faw%2FagDTc1xg%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">首要</span>看电感值，<span style="color: black;">LM</span>2596 47μH，LM53603 2.2<span style="color: black;">μH</span>，LT8641 4.7μH。<span style="color: black;">倘若</span><span style="color: black;">一样</span>的电流，感值<span style="color: black;">仅有</span>其他的1/10，体积就大大的减少了。<span style="color: black;">另一</span>，<span style="color: black;">一样</span>的电流，绕到47μH的感值，要绕<span style="color: black;">非常多</span>圈，铜<span style="color: black;">亦</span>是有铜损的。<span style="color: black;">因此</span>大感值在电源系统里面未必真的是永恒的东西。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">第二看输出电容，标配的规格书上面写的220μF 330μF<span style="color: black;">乃至</span>有470μF的电容，体积很大。<span style="color: black;">然则</span>新的器件三个22μF，差距够大。<span style="color: black;">倘若</span>看占板面积，这个差别更大。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/131c3e00b9fa460d98c0ddf2ef98b83b~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=yvFfOTmTs0cA551IbRJDaEI9Eis%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">LT8641占板面积</span></span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/e02ec3858d3e4da181f75166f40d39fa~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=6zNjw7IyB5qI9N00yAh6sh8E7PE%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">LM53603占板面积</span></span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/ea6a3412717a4e1d80f2bb563c7005af~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=SOi9J02Rv48GWqit2xVQuo4vc%2Bs%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">LM2596占板面积</span></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">从上面几张图<span style="color: black;">能够</span>看出：LM2596电路图，除了LM2596大芯片，还有两个大电容、一个大电感、二极管，一堆东西占板面积很大。而TI的新芯片的占板面积15mm×17mm，ADI的比这个还小，12mm×15mm<span style="color: black;">上下</span>。性能指标毫无疑问<span style="color: black;">必定</span><span style="color: black;">亦</span>是有<span style="color: black;">优良</span>的。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">LM2596还需要一个二极管，这个很经典的二极管。<span style="color: black;">然则</span>LM53603，LT8641这两个电路都<span style="color: black;">无</span>二极管，为了提<span style="color: black;">有效</span>率，在新的设计<span style="color: black;">其中</span><span style="color: black;">已然</span>用MOS管来代替这个续流二级管，<span style="color: black;">咱们</span>叫同步整流，<span style="color: black;">这般</span>会<span style="color: black;">极重</span>地<span style="color: black;">加强</span>系统的效率，<span style="color: black;">况且</span>外面不需要再加二极管，新的电路简单<span style="color: black;">非常多</span>，体积小<span style="color: black;">非常多</span>，性能<span style="color: black;">亦</span>要好<span style="color: black;">非常多</span>。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">指标对比：</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8d50bf658cde4224b827d4041544e19d~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=7jN0rFNHGdV5A3gq8P4GC7i1mQA%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">嵌入式物联网需要学的东西真的非常多，千万不要学错了路线和内容，<span style="color: black;">引起</span>工资要不上去！</span></strong></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">无偿分享<span style="color: black;">大众</span>一个资料包，差不多150多G。里面学习内容、面经、项目都比较新<span style="color: black;">亦</span>比较全！某鱼上买估计<span style="color: black;">最少</span>要好几十。</span></strong></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;"><span style="color: black;">点击<span style="color: black;">这儿</span>找小助理0元领取：<a style="color: black;">嵌入式物联网学习资料（头</a>条）</span></strong></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/52958a6eb5d4403990f22d94f93b14ee~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=dmaaeA6UJetnApaju3Q%2BWORE3Y8%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/73bc9d0a619e44088ce8219119ddf3eb~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=y64j%2FJM%2BLAmty4lQ9rEzkVwkk80%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">以上对比，<span style="color: black;">能够</span>看出经典的东西，<span style="color: black;">由于</span>随着时代的变迁，可能真的不得不被淘汰。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">下面来看一下说Buck/Boost的电路，在设计<span style="color: black;">其中</span><span style="color: black;">咱们</span>需要关注的参数和性能。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;"><span style="color: black;">第1</span>个输入输出电压和输出电流</span></strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">那输入输出电压输出电压<span style="color: black;">不消</span>多讲，与用电设备<span style="color: black;">相关</span>。但输入电压要<span style="color: black;">思虑</span>系统的波动，<span style="color: black;">例如</span>说一个直流5V的适配器热插拔，电压值会冲到九点几V。<span style="color: black;">倘若</span>选6.3V的DC/DC大概率就会烧掉，<span style="color: black;">因此</span><span style="color: black;">咱们</span><span style="color: black;">一般</span><span style="color: black;">意见</span><span style="color: black;">倘若</span>是板级用，选1.5倍的输入电压。<span style="color: black;">倘若</span>是外面插线，最好按2倍来选。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/658494bb43804f35a2d686e6606b431e~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=Px8wHN7OlOwMll2wiqd0%2FkvKm%2Bg%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">电流怎么选呢？<span style="color: black;">倘若</span>系统需要1A的电流，开关电源最好是<span style="color: black;">选取</span>2A<span style="color: black;">上下</span>的，<span style="color: black;">这般</span>有<span style="color: black;">必定</span>的余量，效率<span style="color: black;">亦</span>比较高。<span style="color: black;">然则</span>要<span style="color: black;">重视</span>系统里面瞬间的峰值功率会不会很大，<span style="color: black;">倘若</span>会，还要把这个值往上调。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/e5b2ca3a5f814fccbc8036358b93b0fb~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=GzCDBh1mqvlQDMXqsJNLOgzP0CI%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">第二个开关频率和转化效率</span></strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">除了看系统有<span style="color: black;">无</span>同步整流的二极管影响效率之外，最重要的两个损耗：开关频率越高推动两个MOS管去开关的时候，所需要的能量就越高，这叫开关损耗。<span style="color: black;">由于</span>MOS管本身是有Rds(on)，Gate端有Qg，要驱动Gate端，Rds(on)会产生损耗的话，频率越高，损耗越大。但是频率高的时候电感感值比较小，<span style="color: black;">寓意</span>着电感的内阻比较小，损耗会降低，<span style="color: black;">因此</span>这个平衡<span style="color: black;">便是</span>开关损耗和电感损耗。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/87d831ba78f643bdaf3b525c6aadd11d~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=TTBjbM7b72KousiC88N0ZwZ0nPc%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">当对效率追求极致的时候，<span style="color: black;">咱们</span><span style="color: black;">一般</span>会做<span style="color: black;">区别</span>的开关频率，<span style="color: black;">区别</span>的电感感值，<span style="color: black;">而后</span>去<span style="color: black;">测绘</span>效率点。<span style="color: black;">因此</span>开关频率和转换效率必须要去做平衡的，要么就追求开关频率高，<span style="color: black;">而后</span>很小的体积，<span style="color: black;">然则</span>这个时候效率会低。要么<span style="color: black;">能够</span>把开关频率适当下降，虽然说电感损耗会大一点，<span style="color: black;">然则</span>开关损耗会下来，效率会适当的优化。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">当然还有一点是电路里面有上管下管两个MOS管、一个电感，PWM的波形<span style="color: black;">提升</span>的这个斜率<span style="color: black;">亦</span>会影响到效率。上管和下管是<span style="color: black;">不可</span><span style="color: black;">同期</span>打开的，在系统设计里面都会有一个固定的死区时间，为了避免上管下管直接导通。这个死区时间<span style="color: black;">倘若</span>越大，它对系统效率的影响<span style="color: black;">亦</span>大。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">第三个瞬态响应</span></strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">开关电源的瞬态响应和电路的开关频率、电容的特性有很大关系。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">大众</span>看这个波形：</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/11786517d36a4d0a85cf3c9b8866fe03~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=%2F8xL9p6G7BTfv95vYOJ%2FhLC9f5o%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">这个应该是二三十年前用模拟示波器测的，0.5A到2A的电流变化，它的瞬态响应接近300mV，电压的波动<span style="color: black;">已然</span>很大了。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">然则</span><span style="color: black;">倘若</span>你看新的芯片，0到3A 这个电流比上面的大，但瞬态响应<span style="color: black;">亦</span>就200多mV。如果把电流变化设成500mA到2A，瞬态响应<span style="color: black;">必定</span>是非常小的。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/5b060b15291343d5baffa5efa5b24cef~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=LkMbOu4%2FWuqwmju2WWzxN6AEAvo%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">因此</span><span style="color: black;">咱们</span><span style="color: black;">能够</span>理解为：这两个芯片，频率高的用的陶瓷电容<span style="color: black;">或</span>内阻比较小的，瞬态响应是有优化的。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">第四个静态电流</span></strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">静态电流与芯片的工作模式、芯片设计<span style="color: black;">相关</span>。<span style="color: black;">倘若</span>做板级的设计是工业<span style="color: black;">掌控</span>这种机床，静态电流<span style="color: black;">体积</span>是无<span style="color: black;">所说</span>。但<span style="color: black;">倘若</span>是用的手持设备<span style="color: black;">或</span>用电池供电的设备，静态电流就<span style="color: black;">不可</span><span style="color: black;">忽略</span>。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8517d6346a0d4db3847838fd51673366~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=AZPgjuwJyf4mTyMad9LkUcFnCiM%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">先看经典的LM2596，它有150KHz的开关频率，是固定频率模式，<span style="color: black;">便是</span>不管有<span style="color: black;">无</span>负载，固定频率正在波动，静态在5到10mA。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">看LM53603，有一个自动轻负载模式，2.1M开关频率，<span style="color: black;">然则</span>它的静态电流<span style="color: black;">仅有</span>24个uA，比2596小<span style="color: black;">非常多</span>。而LM8614静态电流就更低，仅有2.5uA。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">第五个纹波和噪声</span></strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">先去简单地看一下纹波和噪声是怎么产生的。这是一个非常经典的Buck电路：</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/a8ee5262bc7243b39d1695e96658d1ea~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=Uy5K6HMTe5NKer4zvReOlfxJ%2Bqc%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">Buck电路的工作在上半周，即上管打开的时候，是<span style="color: black;">经过</span>Vin、上管、电感和负载形成一个环路，<span style="color: black;">这般</span>的话电感就有工作电流。而电感的电流是<span style="color: black;">不可</span>突变的，那当上管关闭、下管打开的时候，这个电感的电流会在输出和下管之间循环。<span style="color: black;">而后</span>PWM波形<span style="color: black;">便是</span>上管、下管交替打开就行了，<span style="color: black;">经过</span>电感的储能释放，实现了电压降压的变换。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">咱们</span>就会<span style="color: black;">发掘</span>下面的电感其实是有个泄放回路的，<span style="color: black;">便是</span>Mbot，给电感续流，<span style="color: black;">然则</span>在输入端的引脚上的寄生电感就<span style="color: black;">无</span><span style="color: black;">那样</span>走运了，当上管打开、关闭的瞬间，<span style="color: black;">这儿</span>面电感的电流<span style="color: black;">无</span><span style="color: black;">地区</span>跑，这是一个很致命的，<span style="color: black;">因此</span><span style="color: black;">这儿</span>面有一个非常大的Hot Loop，<span style="color: black;">便是</span>非常高的di/dt。寄生电感越大，di/dt和Hot Loop对这个系统的EMI和噪声的影响就越大。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/e1e0d1256c534f1c9a4855b54aa86bad~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=citFO5VriTXsypHr4BsvJIm2frI%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">倘若</span>看SW这个点，即两个MOS管的中间节点，就会<span style="color: black;">发掘</span>SW的节点的振铃是会抖动，这<span style="color: black;">亦</span>会<span style="color: black;">引起</span>传播EMI和辐射EMI。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/bfb71bf0c6be41e3834f9e8d9e19f85b~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=RVOWczkrgWEflhSb9MpHXIuIRc0%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">那怎么<span style="color: black;">处理</span>EMI的问题，<span style="color: black;">由于</span>这个抖动振铃越大，纹波和噪声和EMI的问题就越严重。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">倘若</span>在节点的<span style="color: black;">地区</span>并小电容，对系统的性能影响是显而易见的，但这是治标不治本的<span style="color: black;">办法</span>，应该用更好的电路实现低EMI。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">ADI做了一个大胆的创新和尝试，在芯片的输入端做了两个Vin，这两个Vin和地形成两个反向的电流环，两个相反的电流环产生磁场闭合，<span style="color: black;">因此</span><span style="color: black;">大众</span>会看到有两个Vin、两个Cin在电路上对<span style="color: black;">叫作</span>排布。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p26-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/92ed86bf3ac2428fa18cf6f21f7bda28~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=Dglsb1QrSbwsm1AtZVc5rYW4eNk%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">在芯片的内部，硅片是<span style="color: black;">经过</span>经线邦定到框架上引脚出去的，衬底引脚都是电感，<span style="color: black;">因此</span><span style="color: black;">倘若</span>把这个芯片和经线邦定改成用倒装的这种方式，Flip-Chip，<span style="color: black;">便是</span>这个引脚直接贴片出来<span style="color: black;">便是</span>引脚，就会改善<span style="color: black;">非常多</span>。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">LT8610是传统的封装工艺，LT8614是flip chip的封装工艺，显然EMI改善<span style="color: black;">显著</span>。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/8d4e162371344dba8ffbe3631714ddb2~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=ccGdcNf%2BEq5Cbk%2FppukIm8kPB1w%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">这种新的封装工艺和框架结构既<span style="color: black;">处理</span>了效率的问题，<span style="color: black;">亦</span><span style="color: black;">处理</span>了EMI的问题，纹波<span style="color: black;">亦</span>得到优化。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">虽然说</span>Buck和Boost电路有很<span style="color: black;">大都是</span>共性，<span style="color: black;">然则</span>有两个<span style="color: black;">区别</span>的特点。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">Buck电路是最大占空比，</strong><span style="color: black;">尤其</span>是做手持设备的，这是比较重要。手持式设备采用电池供电，<span style="color: black;">倘若</span>想把这个电池用到3.3V，最好的方式<span style="color: black;">便是</span>找一个支持100%占空比的芯片。100%占空比<span style="color: black;">寓意</span>着上管常开、下管常闭，<span style="color: black;">这般</span>的好处是即使电池到了3.3V，输出<span style="color: black;">亦</span><span style="color: black;">能够</span>是3.3V。<span style="color: black;">倘若</span>不凑巧选了一个<span style="color: black;">仅有</span>80%的占空比的芯片，3.3V的20%<span style="color: black;">便是</span>0.66V，那就需要<span style="color: black;">最少</span>3.9V的输入才<span style="color: black;">能够</span>转出3.3V的电压。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/6451aa6501314b1798ea66172c14e7da~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=B8rTExar%2BEfdKcW4%2BNOaJIMAZWY%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">Boost电路则是输出隔离。</strong><span style="color: black;">大众</span>看一下Boost电路内部结构：</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/e385564ee7cf496684af675a1184f2fc~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=bv%2B%2BBw%2B%2BSNnWADTANWbwhHV34DY%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">当芯片不工作（Shut Down）的时候，输入直接就贯穿到Vout。举个例子<span style="color: black;">倘若</span>是2.7V到4.4V转12V，当芯片工作的时候VOUT<span style="color: black;">便是</span>12V没毛病。但当芯片不工作的时候，<span style="color: black;">倘若</span>电池电压是3.5V，3.5V<span style="color: black;">经过</span>L1、体二极管，就直接跑到后面，Vout就有3V到3.5V之间的电压。这个电压可能会让系统的耗电急剧<span style="color: black;">增多</span>，<span style="color: black;">亦</span>有可能让后面需要12V升压的电路<span style="color: black;">处在</span>一个不正常的工作状态，有可能再重新上来就死机了。<span style="color: black;">因此</span>Boost电路升压电路里面支不支持输出隔离是一个非常重要的参数指标。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">怎么实现隔离呢？其实<span style="color: black;">便是</span>做了个背靠背的MOS管，去隔断体二极管，<span style="color: black;">咱们</span>叫Output Disconnect。<span style="color: black;">因此</span>TI、ADI的芯片都有<span style="color: black;">这般</span>的设计，叫真正的输出断接，<span style="color: black;">或</span>是关断时输入输出真正断开。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/c4dd80ed03274971a1cad2f574f1a9ff~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=CdWlQwc2%2FtZeD8pAZCQ02AAotIs%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">开关电源里面还有<span style="color: black;">有些</span>其他的<span style="color: black;">有些</span>信息跟<span style="color: black;">大众</span>做一个简单快速的分享:</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">1）<span style="color: black;">为何</span>要<span style="color: black;">运用</span>外置MOSFET开关电源<span style="color: black;">掌控</span>器？</strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">虽然集成度越高越好，MOS管集成在芯片内部简单，外面挂MOS管太麻烦了。<span style="color: black;">然则</span><span style="color: black;">咱们</span>会看到有的电路还是需要用外置MOS管电路，<span style="color: black;">为何</span>呢？</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">第1</span>，转换效率的问题。之前提过MOS管的Qg和RDS(on)是开关损耗的<span style="color: black;">重点</span><span style="color: black;">源自</span>，<span style="color: black;">然则</span>芯片内部集成的MOS管<span style="color: black;">一般</span>性能指标<span style="color: black;">欠好</span>，RDS(on)比<span style="color: black;">很强</span>，会<span style="color: black;">导致</span>很大的开关损耗。<span style="color: black;">因此</span><span style="color: black;">倘若</span>想要很好的转换效率，<span style="color: black;">必定</span>要选一个非常好的MOS管。但这种好的MOS管是很难被集成到芯片里面去。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">第二，封装和热阻。DC-DC和LDO<span style="color: black;">同样</span><span style="color: black;">亦</span>有热阻的问题，只<span style="color: black;">不外</span><span style="color: black;">由于</span>DC-DC效率比较高，就忽略了热阻的问题。<span style="color: black;">然则</span>你要<span style="color: black;">晓得</span>普通的芯片内置MOS，效率最高<span style="color: black;">亦</span>就到95%<span style="color: black;">上下</span>，还有5%的功率耗散在这个芯片上。<span style="color: black;">倘若</span>电流太大了，即有很大功率热阻。<span style="color: black;">倘若</span>ADI和TI的官网，<span style="color: black;">针对</span>非外置MOS，即内部集成MOS管的芯片电流<span style="color: black;">亦</span>就40A到头了。再往上做，黔驴技穷了。<span style="color: black;">然则</span><span style="color: black;">倘若</span>去找controller，<span style="color: black;">便是</span>外置MOS的<span style="color: black;">掌控</span>器，TI<span style="color: black;">在<span style="color: black;">掌控</span>器的外置MOS的</span>电流可高达 700A， ADI在<span style="color: black;">掌控</span>器的外置MOS的<span style="color: black;">亦</span><span style="color: black;">能够</span>做到400A。<span style="color: black;">因此</span><span style="color: black;">倘若</span>需要大功率、很好的转换效率、极度地优化系统的性能，外置MOS是跑不掉的。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/230b5c9c57e24a949f749395d3b525be~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=xUMyiEmoA0caO5sY9blBNXyKazs%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">运用</span>外置MOS管的开关电源<span style="color: black;">掌控</span>器这是个学问。<span style="color: black;">倘若</span>是新手，<span style="color: black;">意见</span><span style="color: black;">大众</span>先不要这么弄。<span style="color: black;">倘若</span>是新手怎么办呢？<span style="color: black;">选取</span>全集成的，<span style="color: black;">便是</span>把MOS管电感什么都集成，这种ADI叫Micro Module，TI叫MicroSIP。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/64f723f7a8ce4da899669e5137a4c599~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=llwIq%2BoXl9zGIbcxoR2MAUfxj9U%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">电源器件的选型，到<span style="color: black;">这儿</span>基本上讲完了。但还有2个<span style="color: black;">意见</span>给到<span style="color: black;">大众</span>：</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">第1</span>个，必须要学会去各个<span style="color: black;">机构</span>的官网做参数的筛选和检索。</strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;">第二个，电源仿真和PCB Layout哪个重要？</strong></span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">说句实话，<span style="color: black;">倘若</span>你对PCB Layout的布局<span style="color: black;">无</span>任何概念，不<span style="color: black;">意见</span>你天天去依赖于电源仿真，<span style="color: black;">由于</span>数字电路和模拟电路是完全<span style="color: black;">区别</span>的，模拟电路用仿真<span style="color: black;">不可</span><span style="color: black;">处理</span>以下问题：</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">没法</span>优化电路板的阻抗</strong>，<span style="color: black;">由于</span>仿真只是一个连接关系，<span style="color: black;">然则</span>电路里面的阻抗、走线、铜厚、多少个过孔，系统是完全<span style="color: black;">无</span>办法直接去模拟和仿真的。</span></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><strong style="color: blue;"><span style="color: black;">没法</span>模拟电流环路对系统性能的影响</strong>，有时间你当然学电源仿真，没时间那怎么办。最简单的<span style="color: black;">办法</span>，好好地去看规格书。基本上，任何电源芯片的规格书都会给一个布局走线图，<span style="color: black;">例如</span>ADI的LT8641，电感怎么摆，哪个位置打多个孔，<span style="color: black;">所有</span>都给你标出来了。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/a1fc11c74b1349eea1333f9c46ee9ce8~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=FsGUnq5chkxO7T2l%2BiizrtVNpHo%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;"><span style="color: black;">另一</span>还给<span style="color: black;">有些</span><span style="color: black;">意见</span>，在做电源的布局走线的时，<span style="color: black;">必定</span><span style="color: black;">想要</span>办法优化说让电路的走线阻抗越低 越小越好，电流环路越小越好。</span></p>
    <div style="color: black; text-align: left; margin-bottom: 10px;"><img src="https://p3-sign.toutiaoimg.com/tos-cn-i-qvj2lq49k0/4db22ba9e5e94a2d82cf4f1167717535~noop.image?_iz=58558&amp;from=article.pc_detail&amp;lk3s=953192f4&amp;x-expires=1728782260&amp;x-signature=nrSSfYPbeVxGSCRrOJyVuEzxn9I%3D" style="width: 50%; margin-bottom: 20px;"></div>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">原文链接：</p>https://mp.weixin.qq.com/s/Y1ILFn707P6lAcMZ3mB7YQ

    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">文案</span>转载自：达尔闻说</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><span style="color: black;">文案</span><span style="color: black;">源自</span>于：电源芯片大盘点！选型攻略？经典VS新兴哪个好</p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;">原文链接：<a style="color: black;">电源芯片大盘点！选型攻略？经典VS新兴哪个好</a></p>
    <p style="font-size: 16px; color: black; line-height: 40px; text-align: left; margin-bottom: 15px;"><strong style="color: blue;">版权声明：本文<span style="color: black;">源自</span>于网络，免费传达知识，版权归原作者所有，如<span style="color: black;">触及</span>作品版权问题，请联系我进行删除</strong></p>




7wu1wm0 发表于 2024-11-7 14:45:53

这篇文章真的让我受益匪浅，外链发布感谢分享！

7wu1wm0 发表于 2024-11-11 21:24:27

同意、说得对、没错、我也是这么想的等。

wrjc1hod 发表于 昨天 10:34

你的话语如春风拂面，让我心生暖意。

nykek5i 发表于 2 小时前

太棒了、厉害、为你打call、点赞、非常精彩等。
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