This paper presents an autonomous energy management interface for electrostatic series-parallel charge pump vibrational energy harvester. It analysis the feasibility of an ultra low power interface for high voltage output harvesters. It introduces a mixed signal high voltage low power intermediate stage designed in 0.35μm ams CMOS technology, that separates the charge pump Conditioning circuit (CC) and the load. It manages the energy extraction from the CC into a buffer capacitor. The energy is accumulated until there is enough to supply a load. This process is achieved autonomously and using only a pre-charged capacitor to supply the control blocks.