//www.jhzyg.net/tag/%E6%A1%A5%E5%BC%8F%E7%94%B5%E8%B7%AF zh-hans //www.jhzyg.net/content/2022/100557079.html <!-- This file is not used by Drupal core, which uses theme functions instead. See http://api.drupal.org/api/function/theme_field/7 for details. After copying this file to your theme's folder and customizing it, remove this HTML comment. --> <div class="field field-name-body field-type-text-with-summary field-label-hidden"> <div class="field-items"> <div class="field-item even"><p>在<a href="https://techclass.rohm.com.cn/knowledge/sic/a-sic/01-a-sic/9026">上一篇文章</a>中，对SiC MOSFET桥式结构的栅极驱动电路的导通(Turn-on)/关断( Turn-off)动作进行了解说。本文将介绍在SiC MOSFET这一系列开关动作中，SiC MOSFET的VDS和ID的变化会产生什么样的电流和电压。</p><p>下面的电路图是SiC MOSFET桥式结构的同步式boost电路，LS开关导通时的示例。电路图中包括SiC MOSFET的寄生电容、电感、电阻，HS和LS的SiC MOSFET的VDS和ID的变化带来的各处的栅极电流（绿色线）。</p><p><img src="/files/ueditor/108/upload/catcher/20220117/1642409526501234.png" alt="SiC MOSFET桥式结构的同步式boost电路，LS开关导通时的示例" style="margin: 0px; padding: 0px; border: 0px; outline: 0px; vertical-align: baseline; height: auto; max-width: 100%;" /></p><p>ID的变化dID/dt所产生的电压</p><p>ID的变化将会产生下述公式（1）所示的电压。</p><p><img src="/files/ueditor/108/upload/catcher/20220117/1642409526350121.png" alt="ID的变化dID/dt所产生的电压" style="margin: 0px; padding: 0px; border: 0px; outline: 0px; vertical-align: baseline; height: auto; max-width: 100%;" /></p><p><br /></p><p>这是由于存在于SiC MOSFET源极的寄生电感中流过ID而产生的电压，是由电路图中的(I)引起的。该电压会使电流(I’)流过。</p><p>VDS的变化dVDS/dt所产生的电流</p><p>以HS为例，当SiC MOSFET关断、VDS变化时，Gate-Drain寄生电容CGD中会流过电流ICGD。如电路图所示，该电流分为Gate-Source寄生电容CGS侧流过的电流ICGD1：(II)-1和栅极电路侧流过的电流ICGD2：(II)-2。当VDS开始变化时，栅极电路侧的阻抗较大，因此大部分ICGD都在CGS侧，此时的ICGD1如公式（2）所示。</p><p><img src="/files/ueditor/108/upload/catcher/20220117/1642409527485819.png" alt="VDS的变化dVDS/dt所产生的电流" style="margin: 0px; padding: 0px; border: 0px; outline: 0px; vertical-align: baseline; height: auto; max-width: 100%;" /></p><p><br /></p><p>从公式可以看出，当CGD较大时或CGD/CGS的比值变小时，ICGD1会增加。</p><p>dVDS/dt和dID/dt既可以为正也可以为负，所以因它们而产生的电流和电压的极性在导通（Turn-on）和关断（Turn-off）时是不同的。在下一篇文章中将会进一步详细解说。</p><p>文章转载自：<a href="https://techclass.rohm.com.cn/knowledge/sic/a-sic/01-a-sic/9145" target="_self">Rohm</a></p></div> </div> </div> <!-- This file is not used by Drupal core, which uses theme functions instead. See http://api.drupal.org/api/function/theme_field/7 for details. After copying this file to your theme's folder and customizing it, remove this HTML comment. --> <ul class="list-inline"> <li> <a href="/tag/桥式电路"><span class='glyphicon glyphicon-tag'></span> 桥式电路</a> </li> <li> <a href="/tag/sic-mosfet-0"><span class='glyphicon glyphicon-tag'></span> SiC MOSFET</a> </li> </ul> Mon, 17 Jan 2022 08:52:44 +0000 judy 100557079 at //www.jhzyg.net //www.jhzyg.net/content/2022/100557079.html#comments