電壓控制提高傳感器節點效率

　　無線傳感器節點為物聯網的增長提供了驅動力。無線傳感器節點的兩個最重要的方面是，他們應該作出反應，在當地環境的變化和能源效率足夠的生存在一個單一的電池充電多年-可能整個預期壽命的傳感器。為了確保傳感器只對重要的變化作出反應，越來越復雜的軟件將被下載到其中。這反過來，要求高效的處理器，如那些基于32位ARM的放大器皮質的M - M架構，或為簡單的傳感器，改進版本的8位內核，如8051。

　　系統級功耗取決于處理器本身的功率效率的許多變量。為了提高效率，低能量的MCU采用一些智能外設控制的核心處理器為硬件。這些外圍設備工作在不同的時間，將有電力需求，改變在毫秒到毫秒的基礎上。他們需要靈活的電源架構來支持這個

　　The reason for the need to control power to individual parts of the system and even to peripherals integrated into the MCU itself is to support a low duty cycle. The duty cycle determines how long during its lifetime the MCU processor is awake and processing data and how long it is powered down and asleep. A low duty cycle is important because the processor within the system spends almost all of its time asleep in order to save energy.

　　The low duty cycle strategy has proved highly effective in the design of utility meters where the processor core may sleep for 99 percent of its overall life cycle. It wakes only to collect data from sensor inputs， normally at a scheduled time or respond to unscheduled interrupts. Intelligent peripherals support this by checking data from inputs without needing to wake the processor. Only if a threshold is surpassed does the peripheral trigger an interrupt that will cause the processor to handle the change in circumstances. This strategy ensures that only significant changes are processed. Those that imply very little has changed can be queued in memory and handled when the processor core has been woken up for other reasons.