Energy harvesting interface chip uses solar and vibration sources
LTC3330 is an energy harvesting interface chip, mediating between a solar cell or vibration-generator, a local capacitive storage network, a primary cell, a pair of supercapacitors, and a load of up to 50mA through a number of power switches, a buck converter, and a buck-boost converter.
Linear claims that it draws no power at all from the primary cell when harvested energy is available (which is translated to an creditable 10nA max in the data sheet), and only 750nA of operating current when powered from the battery with no load.
Between 3V and 19V ac or dc can be applied to the harvesting input, 1.8V to 5.5V from the primary cell, and 1.2V to 5V can be delivered to the output.
A built-in 25mA 20V Zener clamp stops the harvester from taking the chip out.
A supercapacitor holds up the output, and if two 2.5V supercaps have to be used in series a balancing circuit is built in to prevent over-voltage on either of them.
“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, solar or magnetic sources,” said Linear.
“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.”
Fixed output voltages of: 1.8V, 2.5V, 2.8V, 3.0V, 3.3V, 3.6V, 4.5V or 5V can be pin-programmed.
Input under-voltage lockout threshold settings are programmable between 3V and 18V.
Other features include programmable D-DC and LDO output voltages and buck-boost peak current limits.
LTC3330EUH comes in a 5x5mm QFN-32.
An industrial temperature grade version, 30IUH, is also available.