用于能量收集應(yīng)用的電源管理IC的選擇

　　電源管理IC（PMIC）支持和管理傳感器和能量采集通道、儲(chǔ)能元件（電池，傳統(tǒng)的電容器或超級(jí)電容器），和處理器/無線鏈路。這種能量收集設(shè)計(jì)的關(guān)鍵塊實(shí)現(xiàn)了幾個(gè)主要功能：

　　捕捉和提取隨機(jī)，從源傳感器微小的能量

　　將提取的能量轉(zhuǎn)換為存儲(chǔ)元件的能量，通常是通過DC / DC轉(zhuǎn)換器。

　　管理來自存儲(chǔ)元件的電源流出，同時(shí)確保當(dāng)存儲(chǔ)的能量低于閾值且不會(huì)被浪費(fèi)時(shí)，電源不會(huì)被抽出。

　　也許最具挑戰(zhàn)性的，它必須管理它自己的啟動(dòng)順序從轉(zhuǎn)型的時(shí)候有足夠的可用存儲(chǔ)的能量為PMIC本身

　　用于能量收集系統(tǒng)的設(shè)計(jì)師，也有好消息：對(duì)PMIC的更多的選擇，現(xiàn)在可以從供應(yīng)商，每個(gè)具有不同的屬性和特點(diǎn)。有些是為一個(gè)特定的收獲源優(yōu)化，而其他人更一般；有些實(shí)現(xiàn)是PMIC作用的一部分，而其他人將更多的基本功能。

　　Engineers should always keep in mind that all energy-harvesting designs are based on one principle – to accumulate over time the trickle of minuscule， sporadic energy from the source， store it， and then release it as a power pulse when needed by the rest of the system for data collection， analysis and transmission. Therefore， there are long quiescent periods when the PMIC‘s only activity is to allow the energy to flow to the storage element and little else， as well as periods when there is no incoming energy.

　　You must also be aware that a conventional DC/DC switching converter core， no matter how efficient， is generally not a good choice for energy harvesting. This is because these are designed to work with a consistent source such as battery， which is a low-impedance， somewhat regulated source. Further， the DC/DC switching converter of a PMIC must have extremely low quiescent current requirements， as there may be long periods without available source energy and thus no power-converter activity.