本片主要介绍PCIe总线的电源管理，主要包括不同板卡的功耗、板卡的能耗等级等。
<strong>1、功耗等级</strong>
根据《PCIx系列之“PCIe总线信号介绍”》，PCIe接口的电源包括+12V、+3.3V、+3.3Vaux三种。根据功耗的不同，三种电压的供电能力不同，PCIe卡可以分为以下几种：
<li>10W，直接通过金手指提供；</li>
<li>25W，直接通过金手指提供；</li>
<li>75W，直接通过金手指提供；</li>
<li>150W，需同时通过金手指和2×3Connector提供；</li>
<li>225W，需同时通过金手指和2×4Connector提供；</li>
<li>300W，需同时通过金手指和2×3Connector和2×4 Connector提供；</li>
<center><img src="http://xilinx.eetrend.com/files-eetrend-xilinx/tu_1_0.png" alt=""></center>
<center><img src="http://xilinx.eetrend.com/files-eetrend-xilinx/tu_2.png" alt=""></center>
<center><img src="http://xilinx.eetrend.com/files-eetrend-xilinx/tu_3.png" alt=""></center>
![http://xilinx.eetrend.com/files-eetrend-xilinx/tu_1_0.png"](http://xilinx.eetrend.com/files-eetrend-xilinx/tu_1_0.png"){kind=link}
![http://xilinx.eetrend.com/files-eetrend-xilinx/tu_2.png"](http://xilinx.eetrend.com/files-eetrend-xilinx/tu_2.png"){kind=link}
![http://xilinx.eetrend.com/files-eetrend-xilinx/tu_3.png"](http://xilinx.eetrend.com/files-eetrend-xilinx/tu_3.png"){kind=link}
<strong>2、电源去耦电容要求</strong>
PCIe接口的去耦电容、bulk电容要求如下：
<center><img src="http://xilinx.eetrend.com/files-eetrend-xilinx/tu_4.png" alt=""></center>
![http://xilinx.eetrend.com/files-eetrend-xilinx/tu_4.png"](http://xilinx.eetrend.com/files-eetrend-xilinx/tu_4.png"){kind=link}
<strong>3、电源管理</strong>
PCIe卡和RC建立连接后，Link power management states有如下几种:
<li>L0 – Active state. 是工作状态，所有的PCIe操作都可以进行。</li>
<li>L0s – A low resume latency, energy saving “standby” state. 是节能的待机状态，但是能很快恢复到工作状态。</li>
<li>L1 – Higher latency, lower power “standby” state. 是低能耗的待机状态，需要比L0s更多的时间恢复到工作状态。</li>
<li>L2/L3 Ready – Staging point for L2 or L3.</li>
<li>L2 – Auxiliary-powered Link, deep-energy-saving state. 使用辅助供电，深度节能状态，实现上面属于可选的状态。</li>
<li>L3 – Link Off state. 是完全关闭的状态。</li>
<li>LDn – A transitional Link Down pseudo-state prior to L0.</li>
<center><img src="http://xilinx.eetrend.com/files-eetrend-xilinx/tu_5.png" alt=""></center>
![http://xilinx.eetrend.com/files-eetrend-xilinx/tu_5.png"](http://xilinx.eetrend.com/files-eetrend-xilinx/tu_5.png"){kind=link}
Device Power Management States有如下几种:
<li>D0 State</li>
D0 uninitialized state
D0 active state
<li>D1 State</li>
<li>D2 State</li>
<li>D3 State</li>
D3 hot state
D3 cold state
<center><img src="http://xilinx.eetrend.com/files-eetrend-xilinx/tu_6.png" alt=""></center>
![http://xilinx.eetrend.com/files-eetrend-xilinx/tu_6.png"](http://xilinx.eetrend.com/files-eetrend-xilinx/tu_6.png"){kind=link}
每一种尺寸的卡，在上电时其默认最大功耗是有限制的，可以通过软件配置更高的功率。每种尺寸的卡的默认功率为：
<li>A x1 standard height, half-length card is limited to a 10 W maximum power dissipation.</li>
<li>A x1 low profile card is limited to a 10 W maximum power dissipation.</li>
<li>A x1 standard height, full-length card is limited to a 10 W maximum power dissipation at initial power up. When the card is configured for high power, by default, it must not exceed a 25 W maximum power dissipation oroptionally it must not exceed a 75 W maximum power dissipation.</li>
<li>A x4/x8 or a x16 standard height or low profile card is limited to a25 W maximum power dissipation at initial power up. When a card is configured for high power, it must not exceed a 75 W maximum power dissipation. </li>
文章转载自： <span id="profileBt"><a href="https://mp.weixin.qq.com/s?__biz=MzU0NzE4NDY0Ng==&mid=2247484411&am…;硬件助手</a></span>