Maxim Integrated Products announces the MAX17710, an IC that integrates all of the power-management functions required for ambient energy harvesting, as well as for charging and protecting micro-energy cells (MECs), which are a type of solid-state battery. Running at a very low current level, the MAX17710 accepts energy from several poorly regulated energy harvesting sources with output levels ranging from 1 uW to 100 mW. Examples: Light captured by photovoltaic cells, vibration captured by a piezoelectric element, heat captured by a thermoelectric generator, and RF such as near-field communications.
The MAX17710 includes a programmable input boost regulator and does not require any expensive external components to charge an MEC with energy sources as low as 0.8 V. It also protects the MEC via a linear shunt-series regulator. An ultra-low-quiescent current, adjustable low-dropout linear regulator (LDO) with selectable voltages of 3.3, 2.3, or 1.8 V helps the MAX17710 adapt to a variety of loads.
Packaged in a low-profile 0.5 mm TQFN, the new IC enables a new class of thin, card-like applications. It will also be available in wafer form to enable even thinner form factors. The MAX17710 is suitable for powered smart cards, real-time clock (RTC)/memory backup applications, and wireless sensor networks. Examples of such networks include remote applications like irrigation valve control, building energy management, machine monitoring systems, medical applications, and portable consumer electronics.
For the new product, Maxim worked with Infinite Power Solutions Inc., the manufacturer of THINERGY solid-state, rechargeable MEC battery products. These postage-stamp-sized energy storage products offer low self-discharge rates, enabling years of shelf life and providing reliable backup power.
To protect the MEC from overvoltage conditions, the MAX17710 regulates the input voltage and can shunt excess power. An ultra-low-quiescent current, undervoltage protection circuit prevents potentially damaging overdischarge of the MEC. The undervoltage protection recovers only when an external energy source raises the voltage of the MEC back into a safe zone.
The MAX17710 also finds use in power-bridging applications where energy harvesting isn't necessarily used. In these 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. If grid power is lost or a system brownout occurs 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 can replace coin cells and supercapacitors that have high self-discharge currents and limited life, especially at elevated temperatures.
For more information, contact Maxim Integrated Products, 120 San Gabriel Dr., Sunnyvale, CA 94086. Phone: (408) 737-7600.
