智能城市無線傳感器網絡能量采集功率管理

　　城市是物聯(lián)網的完美環(huán)境。傳感器可以被用來提供有用的數(shù)據，為許多不同的應用程序，和相對較小的數(shù)據包意味著無線鏈路的比特率可以被交易掉，用于低功耗。這是至關重要的網絡與成千上萬甚至數(shù)百萬的節(jié)點。世界各地的項目都在尋找從環(huán)境中獲取能量來獲取這些傳感器節(jié)點的方法。太陽能，熱，振動，甚至射頻能量都被評估為動力源。

　　這不同于長距離廣域網絡，如蜂窩，需要覆蓋傳感器，可以部署在許多英里。這里的能量要求的無線鏈路往往可以排除使用能源收集源。

　　相反，城市的節(jié)點可以使用一系列不同的低功耗無線協(xié)議從亞GHz的低功耗遠程網絡（lpwan）到2.4 GHz的智能藍牙和ZigBee技術以及專有的網狀網絡。

　　As the energy harvesting sources have variable， low currents， there are highly specialized requirements for the power management unit （PMU） in order to provide the wireless transceiver， microcontroller， and sensor with power.

　　Despite increasing integration in the PMU， the design of the energy harvesting power supply for such wireless nodes requires attention to the capacitors and inductors to deliver the optimum power.

　　The Analog Devices ADP5091 PMU can be used to convert DC power in the 6 μW to 600 mW range to cope with the variations from photovoltaic （PV） cells or thermal energy generators （TEGs） for wireless sensor nodes. These devices charge storage elements such as rechargeable Li-Ion batteries， thin film batteries， supercapacitors， or conventional capacitors to provide a steady current for the sensors. This can also supply the higher power required for the transceiver to send the data to a local gateway.

　　A key element of the design is an internal cold start circuit so that the regulator can start operating at an input voltage as low as 380 mV. After cold startup， the regulator can handle an input voltage range of 0.08 V to 3.3 V and an additional 150 mA regulated output can be programmed by an external resistor divider or the VID pin in Figure 1.