The study conducted addresses a vibrational energy harvester (VEH) based on a microelectromechanical system (MEMS) with a gap-closing electrostatic resonator. The harvester consists of a charge pump system in the form of a rectifier with feedback with an ultra-low-power (ULP) comparator as output. The latter regulates the harvesting cycle of the system using a bulk-driven topology. The complete circuit is implemented in a 180 nm silicon technology. The designed energy harvester generates an output power of 65.45nW at an acceleration of 0.35m/s2 and a frequency of 53.5Hz. The implemented circuit is supplied with a voltage of one volt and has an average power consumption of 7nW in the operating range. All simulations were conducted using Cadence Virtuoso.