The most widely used AC/DC architecture in low-power harvesting applications is made up of a passive diode bridge rectifier and a DC/DC converter. The latter usually implements a maximum power point tracking technique (MPPT) in order to dynamically ensure the maximum power extraction from the harvester. In this paper, the performance of the Open-Circuit Voltage MPPT technique is investigated as a function of the piezoelectric harvester characteristics, of the input vibration characteristics and of the DC/DC converter control speed. Through a theoretical and numerical analysis, it is shown that a proper design of the Open-Circuit Voltage MPPT technique can lead to a significant increase of the power extraction, which in the considered examples reached 54%.