電源管理IC簡(jiǎn)化集成超級(jí)電容器的能量microharvesting設(shè)計(jì)

　　能源microharvesting應(yīng)用如無線傳感器節(jié)點(diǎn)需要周期性的爆發(fā)力量遠(yuǎn)遠(yuǎn)超出大多數(shù)環(huán)境來源的穩(wěn)態(tài)可用。在這方面，超級(jí)電容器提供了非常適合于能量收集環(huán)境的性能特性。由超級(jí)電容器適當(dāng)?shù)墓β屎统潆姽芾黼娐废嘟Y(jié)合，利用從制造商包括線性技術(shù)，集成的專業(yè)設(shè)備，和德克薩斯的工具，工程師可以利用microharvesting技術(shù)應(yīng)用要求的峰值功率要求。

　　電化學(xué)雙層電容器（電容器），或超級(jí)電容器，能夠排出幾十甚至幾百毫安的電流在幾秒鐘的過程（見高新區(qū)的文章“超級(jí)電容器滿足能量收集應(yīng)用的獨(dú)特需求）。例如，對(duì)于無線傳感器節(jié)點(diǎn)應(yīng)用而言，這種功率輸出在無線通信突發(fā)的峰值需求包中很好。超級(jí)電容器的高效充放電循環(huán)使其非常適合于突發(fā)式應(yīng)用，如無線傳感器節(jié)點(diǎn)。

　　Similarly， their efficient charge/discharge characteristics make them well suited to specialized demands of microharvesting applications that must periodically “cold boot” after an extended absence of ambient energy has depleted all onboard charge storage devices. Here， the full application circuitry is reenergized sequentially after microharvesting circuitry first charges a bootstrap supercapacitor used to power subsequent stages of the bootstrap process.

　　A typical microharvesting application uses supercapacitors as the sole storage device or as supplemental storage for peak or cold boot requirements （Figure 1）。 For load management， a DC/DC converter is required to maintain a stable supply voltage to the load because the voltage output of a supercapacitor is linearly proportional to the charge on the supercap. Engineers will typically use a buck-boost converter with low dropout to extract maximum power from the supercap even as charge levels drop under load.