Energy Harvesting PMICs (power management integrated circuits)
Flexible, low-power power management integrated circuits (PMICs) for energy-harvesting IoT devices. Energy harvesting is the process by which energy is derived from external sources (e.g. solar or light energy, thermal energy and kinetic energy) and stored for small, wireless autonomous devices like those used in wireless sensor nodes (WSNs). Energy harvesting devices (EHDs) provide a small amount of power for low-energy electronics. Solar modules are a popular EHD, since they are readily available, easy to use and low cost. The power generated is proportional to the the size of module and varies with brightness. Piezoelectric and electromagnetic EHDs generate AC power from kinetic energy such as vibration. They can generate large amounts of power with high voltage, but the challenge for these EHDs is to provide a vibration source of constant predictable frequency. Because of this, a typical application for a vibration EHD is attaching to a motor. A thermoelectric generator (TEG) can generate power with high current from heat. Similar to the vibration EHD, a constant temperature gradient for the device must be maintained to provide usable power.
An energy harvesting PMIC is part of an energy harvesting system (EHS) that includes the EHD and a storage device. The PMIC receives the intermittent, very low-energy generated by the EHD and transforms that energy for storage in the storage device, which is typically a battery, conventional capacitor or super capacitor that then is connected to the rest of the system, providing the power needed to operate.