Patent ID: 6894618

Claim:
A method for maintaining the oscillations of a vibrating device intended to be fitted to a unit worn close to the body, for use in a timepiece, including a case, a moving mass inside said case intended to transmit vibrations thereto, a coil electromagnetically coupled to said moving mass in order to make it oscillate, and an excitation circuit for exciting said coil, said method consisting in generating, by means of said excitation circuit, a set of driving pulses of alternate polarity and of determined duration substantially coinciding with extremes of movement induced voltage produced across terminals of said coil, wherein each driving pulse is generated at the end of a determined and non-variable time interval considered from a mean level crossing of said movement induced voltage, the time interval taken by said movement induced voltage to reach said mean level crossing at the end of a driving pulse being determined by the instantaneous natural oscillation frequency of the vibrating device, such that an adaptation of the frequency at which said driving pulses are generated is carried out.