Trigger circuits in battery-less multi-source power management electronics for piezoelectric energy harvesters

With reference to multi-source vibration energy harvesting based on simultaneous use of multiple piezoelectric converters, this work proposes and experimentally validates two innovative power management circuits based on custom trigger circuits to overcome the limitations related to the traditional approaches. The proposed series-like topology allows to power a load from multiple series-connected capacitors, each with different levels of stored energy preventing the reverse current flow in the less charged capacitors. The proposed parallel-like topology is able to extract the energy from each one of multiple converters and charge a single storage capacitor even when the voltage across the storage capacitor becomes larger than the converter output voltages.