Nanopower DC/DC converter drives wireless sensor networks

August 05, 2013 // By Jean-Pierre Joosting
The LTC3330 from Linear Technology is a complete regulating energy harvesting power supply that delivers up to 50 mA of continuous output current to extend battery life when harvestable energy is available.

The LTC3330 nanopower converter requires no supply current from the battery when providing regulated power to the load from harvested energy and only 750 nA operating when powered from the battery under no-load conditions. The device 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 1.8 V to 5.5 V 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 the battery when the harvesting source is no longer available.

The LTC3330’s energy harvesting inputs operate from a voltage range of 3 V to 19 V, AC or DC, making it ideal for a wide array of piezoelectric, solar or magnetic energy sources. Its input undervoltage lockout threshold settings are programmable between 3 V and 18 V, 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 25 mA at VIN >20 V).