Energy-harvesting, nanopower buck-boost DC/DC extends battery life

August 05, 2013 // By EDN
LTC3330 is a complete regulating energy harvesting solution that delivers up to 50mA of continuous output current to extend battery life when harvestable energy is available.

The LTC3330 requires no supply current from the battery when providing regulated power to the load from harvested energy and only 750nA operating when powered from the battery under no-load conditions. The LTC3330 integrates a high voltage energy harvesting power supply, plus a synchronous buck-boost DC/DC converter powered by a primary cell battery to create a single non-interruptible output for energy harvesting applications such as those in wireless sensor networks. The energy harvesting power supply, consisting of a full-wave bridge rectifier accommodating AC or DC inputs and a high efficiency buck converter, harvests energy from piezoelectric (AC), solar (DC) or magnetic (AC) sources. The primary cell input powers a buck-boost converter that operates from 1.8V to 5.5V at its input when harvested energy is not available to regulate the output whether the input is above, below or equal to the output. The LTC3330 automatically transitions to battery supply when the harvesting source is no longer available.

The LTC3330’s energy harvesting inputs operate from a voltage range of 3V to 19V, AC or DC, making it suitable for a wide array of piezoelectric, solar or magnetic energy sources. Its input undervoltage-lockout threshold settings are programmable between 3V and 18V, enabling the application to operate the energy harvesting source at its peak power transfer point. Other features include programmable DC/DC and LDO output voltages, buck-boost peak current limits, supercapacitor charger/balancer and an input protective shunt (up to 25mA at V IN >20V).

The LTC3330EUH occupies a 5 x 5mm QFN package and costs $3.55 (1,000)-piece quantities. An industrial temperature grade version, the LTC3330IUH, is also available at $3.90.

Linear Technology; www.linear.com/product/LTC3330