Alpha Micro has further extended its portfolio of wireless components that draw energy from the environment with the introduction of the IPS-EVAL-EH-01, a universal energy-harvesting evaluation kit for autonomous wireless sensors and other sub-100mW applications. Developed by Infinite Power Solutions, the kit features the company’s award-winning THINERGY® MEC201 solid-state, rechargeable, micro-energy cell (MEC) – a unique type of thin-film battery with industry-leading performance and the recently released MAX17710 from Maxim Integrated Products, the industry’s first complete power-management integrated circuit (PMIC) solution for energy harvesting and battery protection. Ideal for design engineers keen to develop and evaluate self-sustaining “green’’ power supply solutions, displacing the use of conventional batteries and super capacitors that require frequent replacement, it can also be used to power popular third-party micro-controller and radio module development kits, enabling users to create and evaluate a variety of self-powered microelectronic applications.
The IPS-EVAL-EH-01 circuit board footprint is similar to a credit card and consists of three key elements: energy harvesting, energy storage and energy management. Due to the unique and ultra-low quiescent current of the integrated PMIC, and the low self-discharge rate of the integrated THINERGY MEC201, the IPS-EVAL-EH-01 evaluation kit efficiently accepts charge currents less than one microampere, making it ideal for storing harvested energy. An amorphous silicon photovoltaic solar array is integrated for out-of-the-box functionality and recharges the MEC201 to a 100 percent state of charge in about 30 minutes in full sun and in approximately eight hours in typical office lighting (~1,500 lux). In addition, the board provides an interface to any type of external ambient energy-harvesting transducer. Example energy sources include light (captured by a variety of photovoltaic technologies), vibration (from a piezo-electric element), heat (via thermo-electric generator), and radio-frequencies (captured by a RF harvester or near-field communications (NFC) receiver. The kit also features an interface header and 6-pin connector that are compatible with popular micro-controller and low power radio development kits available from a variety of leading semiconductor and module manufacturers such as Anaren, BlueRadios, Energy Micro, Microchip, Silicon Laboratories and Texas Instruments.
Harvested energy is efficiently stored in a THINERGY MEC201-7S, which is a 4V, 0.7 mAh capacity rechargeable battery ideally suited for energy-harvesting applications. The MEC201-7S is a thin, flexible, solid-state and near loss-less energy storage cell the size of a postage stamp. Self-discharge is so low and insignificant that energy can be reliably stored for decades on a single charge. IPS continues to lead the industry in delivering the most efficient and powerful batteries in its size class – outperforming all other energy storage technologies currently on the market, such as supercapacitors, coin cells, printed batteries and other thin-film batteries.
Extremely small, powerful and robust, the MEC201 features a unique, patented, flexible package design that maximizes the active area of the cell to deliver high energy and power density. The MECs can be stacked vertically in a parallel configuration for more power and capacity without consuming additional system footprint. For example, a five cell MEC201 stack is approximately 1mm in total height and delivers an amazing 200mA of continuous discharge current (approximately 0.5W of power). The MEC201 can recharge to 90 percent in only 15 minutes and can be recharged more than 10,000 times. With an expected lifetime of up to 20 years, THINERGY MECs require no maintenance or periodic replacement compared to other batteries and supercapacitors, allowing for the lowest total cost of ownership. Moreover, THINERGY MECs contain no heavy metals, are eco-friendly and completely safe. As a result, THINERGY MECs are changing how the power source for micro-electronic systems is being designed, both now and in the future.
Efficient energy management is achieved by the MAX17710 PMIC, the industry’s first IC to integrate all of the power-management functions for ambient energy harvesting, charging, and protecting THINERGY MECs. Operating at an ultra-low current level measured in nanoamps, the MAX17710 accepts energy from a variety of poorly regulated energy harvesting sources with output levels ranging from 1µW to 100mW. The device integrates a programmable input boost regulator and needs no expensive external components to charge a MEC with energy sources as low as 0.8V. It protects the MEC by using a linear shunt-series regulator. An integrated, ultra-low-quiescent current, adjustable low-dropout linear regulator (LDO) with selectable voltages of 3.3V, 2.3V or 1.8V, allows the MAX17710 to adapt to a variety of loads. Packaged in a low-profile 0.5mm TQFN, it enables a new class of ultra-thin applications.
Applications for this combination of energy harvester, THINERGY MEC and MAX17710 PMIC include remote/autonomously powered wireless sensors, biometric security systems, remote controls, memory and real-time clock (RTC) back up, asset tracking, semi-active RFID tags, powered smart cards, smart home and building energy-management, machine monitoring systems, medical applications, and a myriad of portable consumer electronics.