Unstable charge pumps used as rectifier circuits for triboelectric generators, like the Bennet's doubler, have been proven to drastically improve the harvested power compared to traditional diode bridges, at the cost of longer starting time. In this work, we propose for the first time a kinetic energy harvesting system based on the Bennet's doubler, polarizing two triboelectric transducers with antiphasic capacitance variations, instead of just one triboelectric transducer. We show that this configuration reduces the time needed to reach the circuit's unstable regime compared to its single-transducer counterpart. Consequently, the harvested power is increased.