Stepping motor drive controlling circuit

摘要

A controlling circuit for a stepping motor provided on a disk recording and reproducing apparatus which circuit can prevent outputting of a zero track signal in error that may be caused by a stepping error to assuredly step a head to the zero track of a disk. The circuit comprises an excitation initializing circuit which is operable in response to a power on signal and a drive select signal for sequentially switching the exciting mode of the stepping motor from the &upbar& A phase mode to the AB phase mode.