A new resonant pulse converter for energy harvesting is proposed. The converter transfers energy from a low-voltage AC current to a battery. The low-voltage AC current source is an equivalent of the piezoelectric generator, which converts the mechanical energy to the electric energy. The converter consists of a full-bridge rectifier having four N-type MOSFETs and a boost converter haying N-type MOSFET and P-type MOSFET instead of diode. Switching of MOSFETs utilizes the capability of the $3^{rd}$ regional operation. The operational principles and switching method for the power control of the converter are investigated with the consideration of effects of the parasitic capacitances of MOSFETs. Simulation and experiment are performed to prove the analysis of the converter operation and to show the possibility of the $mu$W energy harvesting.