發(fā)展低功率感應(yīng)系統(tǒng)的能源預(yù)算-第二部分：權(quán)力預(yù)算藝術(shù)

　　開發(fā)一種確保產(chǎn)品達到目標(biāo)服務(wù)壽命的能源預(yù)算可以是一種“黑色藝術(shù)”，但也有一些相對簡單的技術(shù)可以幫助工程師實現(xiàn)性能和功耗的正確平衡。本系列的第一部分提供了在低功耗無線節(jié)點中通常找到的系統(tǒng)元素的運行情況，并查看了最常用的能量收集和電池單元的容量和特性。這第二部分將提供一個簡單的方法來開發(fā)一階能量預(yù)算，可用于確保預(yù)定的能量收集系統(tǒng)或電池大小適當(dāng)?shù)脑O(shè)計。接下來是一些微調(diào)設(shè)計的策略，以延長使用壽命或適應(yīng)現(xiàn)有電源的局限性。

　　Define your requirements

　　Both the system and its energy budget begin with a thorough definition of its intended mission， the activities it will perform， and the desired service lifetime （Figure 1）。 Some important parameters to consider include：

　　Service Environment – What is the system‘s service life and operating temperature range？

　　Sampling Modes/Sampling Rates– What analog and digital inputs should the design monitor， and how frequently？ Which inputs are sampled on a scheduled basis and which ones are triggered by outside stimulus？

　　How much data is collected and how much local processing is applied to the data？

　　Does the system communicate with other nodes or a host node？ If so， is it via wired or wireless link？

　　How often does the system communicate， and how much data is exchanged in the process？

　　From these requirements， the engineer can develop a preliminary design using a low-power MCU and any additional LDOs， RTC/timers， I/O or communication circuitry the application requires.