Harvesting energy from environmental sources has been of particular interest these last fewyears. Microgenerators that can power electronic systems are a solution for the conceptionof autonomous, wireless devices. They allow the removal of bulky and costly wiring,as well as complex maintenance and environmental issues for battery-poweredsystems. In particular, using piezoelectric generators for converting vibrationalenergy to electrical energy is an intensively investigated field. In this domain,it has been shown that the harvested energy can be greatly improved by theuse of an original non-linear treatment of the piezoelectric voltage called SSHI(Synchronized Switch Harvesting on Inductor), which consists in intermittently switchingthe piezoelectric element on a resonant electrical network for a very short time.However, the integration of miniaturized microgenerators with low voltage output(e.g. MEMS microgenerators) has not been widely studied. In the case of lowvoltage output, the losses introduced by voltage gaps of discrete components suchas diodes or transistors can no longer be neglected. Therefore the purpose ofthis paper is to propose a model that takes into account such losses as well as anew architecture for the SSHI energy harvesting circuit that limits such lossesin the harvesting process. While most of the study uses an externally poweredmicrocontroller for the non-linear treatment, this circuit is fully self-powered, thusproviding an enhanced autonomous microgenerator. In particular this circuitaims at limiting the effect of non-linear components with a voltage gap such asdiodes. It is shown both theoretically and experimentally that the harvested powercan be significantly increased using such a circuit. In particular, experimentalmeasurements performed on a cantilever beam show that the circuit allows a160% increase of the harvested power compared to a standard energy harvestingcircuit, while the classical implementation of the SSHI shows an increase of only100% of the output power in the classical case.