Arrow Electronics Offers
Turnkey Energy-Harvesting Reference Design
Teams with industry-leading suppliers to provide comprehensive, self-sustaining, ultra-low-power wireless sensor network solution
June 16, 2011 10:24 AM Eastern Daylight Time
MELVILLE, N.Y.–(EON: Enhanced Online News)–Arrow Electronics, Inc. has joined with leading suppliers Silicon Labs, Infinite Power Solutions and Linear Technology Corporation to launch a turnkey energy-harvesting reference design enabling wireless networks powered by a solar energy-harvesting source.
“Working together with industry leaders Silicon Labs, Infinite Power Solutions and Linear Technology, we’ve developed a complete solution that can help customers reduce the complexity and enhance the sustainability of a variety of wireless networking applications”
The energy-harvesting reference design offers a simple, cost-effective bill of materials based on several key components. The design includes a solar-powered wireless sensor node that measures temperature, light level and charge level. It uses Silicon Labs’ ultra-low-power Si10xx wireless microcontroller (MCU) to control the sensor system and transmit data wirelessly. It also incorporates a thin-film battery to store harvested energy, as well as a battery charger IC for efficient power management. The data is transmitted to a wireless USB adapter included with the reference design that connects the wireless sensor node to a PC where sensor data for up to four nodes is displayed via an easy-to-use network GUI.
“Working together with industry leaders Silicon Labs, Infinite Power Solutions and Linear Technology, we’ve developed a complete solution that can help customers reduce the complexity and enhance the sustainability of a variety of wireless networking applications,” said David West, vice president of supplier marketing and asset for Arrow Electronics.
Silicon Labs’ Si10xx wireless MCUs offer very low active current of 160 µA/MHz and very low sleep mode current, as low as 25 nA, to conserve system resources. The Si10xx MCUs can also wake up very quickly in 2 µS. An on-chip wireless transceiver enables 20 dBm output power and RF sensitivity of -121 dBm, greatly increasing the wireless range. An integrated dc-dc switching regulator enables a wide input voltage range of 0.9V to 3.6V, which is particularly useful in energy-harvesting applications where outputs typically vary.
The reference design uses a THINERGY® solid-state, rechargeable, micro-energy cell (MEC), a unique type of thin film battery, with a capacity of 0.7 mAh developed by Infinite Power Solutions. In direct sunlight, the battery can be recharged fully in only one hour. While in sleep mode, the wireless sensor node will retain a charge for 7,000 hours. If the wireless system is transmitting continuously, it will operate non-stop for about three hours, although it is designed to constantly recharge itself at an appropriate level to keep the MEC from completely discharging.
Linear’s LTC4071 battery charger IC provides additional power management and offers an easy-to-use shunt battery system for Li-ion/Polymer batteries that integrates a charger and battery pack protection into one IC.
The LTC4071, with its 550 nA operating current, charges and protects batteries from previously unusable very low current, intermittent or continuous charging sources.
The LTC4071 can charge at currents up to 50 mA. A near zero (0.1 nA ) low-battery-latching disconnect function protects even low-capacity batteries from deep discharge and potentially irreparable damage. With pin-selectable settings of 4.0 V, 4.1 V or 4.2V, the LTC4071 IC’s 1 percent accurate battery float voltage allows the developer to optimize the balance between battery capacity and lifetime.
Silicon Labs’ wireless sensor energy-harvesting reference design accommodates a wide range of harvested energy sources. An on-board bypass connector gives developers the flexibility to tap other energy-harvesting sources such as vibration, thermal and RF.