McDermott Will & Emery LLP
Drive control circuit for linear vibration motor
A drive signal generating unit generates a drive signal used to alternately deliver a positive current and a negative current to a coil with a nonconducting period inserted between conducting periods. A driver unit generates a drive current in response to the drive signal generated by the drive signal generating unit and supplies the drive current to a coil. The drive signal generating unit estimates the eigen frequency of a linear vibration motor based on a detected position of the zero cross occurring in the coil during the nonconducting period, and the frequency of the drive signal is brought close to the estimated eigen frequency. The zero-cross detecting unit sets a detection window for avoiding the detection of zero cross of voltages other than the induced voltage. The zero-cross detecting unit enables a zero cross detected within the detection window and disables a zero cross detected outside the detection window.
Sanyo Semiconductor Co., Ltd. Semiconductor Components Industries, LLC
H
H02P
inventional
Tsutomu
Murata