Maxim recently débuted the MAX17710, integrating all of the power management functions for ambient energy harvesting, as well as for charging and protecting micro-energy cells (MECs), a form of solid-state battery.
Operating at an ultra-low current level, the IC accepts energy from a variety of poorly regulated energy harvesting sources with output levels ranging from 1 μW to 100 mW. Examples include light (captured by photovoltaic cells), vibration (captured by a piezoelectric element), heat (captured by a thermoelectric generator) and RF (eg, near-field communications (NFC)).
The MAX17710 integrates a programmable input boost regulator and needs no expensive external components to charge a MEC with energy sources as low as 0,8 V. It protects the MEC by using a linear shunt series regulator. A low quiescent current, adjustable low-dropout linear regulator (LDO) with selectable voltages of 3,3 V, 2,3 V or 1,8 V allows the device to adapt to a variety of loads. Packaged in a low-profile 0,5 mm TQFN, the chip enables thin, card-like applications. It will also be available in wafer form to enable even thinner form factors.
At very low temperatures, all batteries exhibit increased characteristic impedance, which limits high pulse currents to the application loads. The MAX17710 integrates a feature that manages an external storage capacitor to augment the battery output and provide high pulse currents, even at very cold temperatures down to -40°C.
The device also works in power bridging applications where energy harvesting is not necessarily used. In such applications, infrastructure power (from the grid or a larger battery) is typically available to power the system and can trickle-charge an MEC for memory or RTC backup power. In the event of a loss of grid power or a system brownout during replacement of the larger system battery, the stored energy in the MEC continues to power volatile memory and/or an RTC for hours, days or even weeks. This solution displaces bulky coin cells and supercapacitors that have high self-discharge currents and limited life, especially at elevated temperatures.
The MAX17710 is targeted at powered smartcards, real-time clock (RTC)/memory backup applications and wireless sensor networks. Examples of wireless sensor networks include remote applications like irrigation valve control, building energy management, machine monitoring systems, asset tracking, biometric security systems, medical applications and a myriad of portable consumer electronics.
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