| 摘要 |
<P>PROBLEM TO BE SOLVED: To minimize influence by periodic width change when adaptively controlling the periodic width of a driving signal so as to make the natural frequency of a linear vibration motor coincide with the frequency of the driving signal. <P>SOLUTION: A driving signal creating part 10 creates the driving signal alternately running a positive current and a negative current to a coil L1 with a non-energizing period interposed. A driving part 20 creates a drive current according to the driving signal created by the driving signal creating part 10 and feeds it to the coil L1. An induced voltage detection part 30 detects an induced voltage generated in the coil L1 during the non-energizing period. A zero cross detection part 40 detects the zero cross of the induced voltage detected by the induced voltage detection part 30. The driving signal creating part 10 estimates the natural frequency of the linear vibration motor 200 from the detection position of the zero cross, and makes the frequency of the driving signal close to the natural frequency. At that time, the driving signal is adjusted so as to keep a ratio of the energizing period to the non-energizing period of the driving signal, even when the frequency width of the driving signal is changed. <P>COPYRIGHT: (C)2011,JPO&INPIT |
