Patent ID: 8547048

Claim:
A drive control circuit of a linear vibration motor, having a stator and a vibrator at least one of which is constituted by an electromagnet, which vibrates the vibrator relative to the stator by supplying a drive current to a coil of the electromagnet, the drive control circuit comprising: a drive signal generating unit configured to generate a drive signal used to alternately deliver a positive current and a negative current to the coil with an nonconducting period inserted between conducting periods; a driver unit configured to generate the drive current in response to the drive signal generated by said drive signal generating unit so as to supply the drive current to the coil; an induced voltage detector configured to detect an induced voltage occurring in the coil during the nonconducting period; and a zero-cross detecting unit configured to detect a zero cross of the induced voltage detected by said induced voltage detector, wherein said drive signal generating unit estimates an eigen frequency of the linear vibration motor based on a detected position of the zero cross thereof, and the frequency of the drive signal is brought close to the estimated eigen frequency, and wherein said zero-cross detecting unit sets a detection window for avoiding the detection of zero cross of voltages other than the induced voltage, and said zero-cross detecting unit enables a zero cross detected within the detection window and disables a zero cross detected outside the detection window.