An efficient Piezoelectric energy-harvesting interface Circuit

Energy harvesting is an emerging technology with applications to handheld, portable, and implantable electronics. Harvesting ambient vibration energy through piezoelectric (PE) means is a popular energy-harvesting technique that can potentially supply 10’s-100’s of μW of available power [1]. One of the limitations of existing PE-harvesters is in their interface circuitry. Commonly used full-bridge rectifiers and voltage doublers [2] severely limit the electrical power extractable from a PEharvesting element. Further, the power consumed in the control circuits of these harvesters reduces the amount of usable electrical power. This work presents a bias-flip rectifier that can improve upon the power extraction capability of existing full-bridge rectifiers by greater than 4X. An efficient control circuit with embedded DCDC converters that can share their filter inductor with the bias-flip rectifier, thereby reducing the volume and component count of the overall solution, is demonstrated.