In this episode Shahriar investigates some state-of-the-art energy harvesting ICs from Linear Technology. The LTC3105 is a highly efficient 400mA Step-Up DC/DC Converter with Maximum Power Point Control and 250mV Start-Up. After exploring the IC’s internal block diagram, the evaluation board for this energy harvesting chip is presented. Various experiments, including the calculation of efficiency, maximum power delivery, start-up behavior and MPPC are presented. As a last experiment, a two stage energy harvesting setup using a solar panel and a super-capacitor capable of charging an iPhone is demonstrated.
The second IC of interest is the LTC3109 which is an Auto-Polarity, Ultralow Voltage Step-Up Converter and Power Manager Energy Harvesting chip. The block diagram and the evaluation board of this IC is presented. The ultra-low voltage capability of the circuit is demonstrated through the use of a Peltier cooler thermo-electric component to generate a 5V output voltage. As a final experiment, several ice cubes are used in conjunction with the thermo-electric generator in order to harvest enough energy to charge an iPhone for 30 seconds.