In this work, we have successfully implemented an electrostatic transducer in a charge-pump circuit for harvesting the energy from the mechanical vibrations. The transducer is an improved and mechanically reliable version of the resonant capacitive bulk-Si vibration energy harvester that we previously presented in [1]. Despite the low transducer volume of 27 mm3, the targeted external vibration is a harmonic acceleration at 250 Hz of 0.25 g. We demonstrate a harvested power of 103 nW converted from the mechanical to the electrical domain. We have compared the measurements with an accurate mixed VHDL-AMS/Eldo model of the system. The modeling predicts currents and voltages evolution with an inaccuracy of less than 3%.