| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency adjusting method capable of shortening adjustment time of drive frequency and sufficiently driving an electronic apparatus, and to provide a frequency adjusting circuit capable of achieving the adjusting method, having a small circuit scale and capable of being formed as one chip.SOLUTION: A frequency adjusting circuit is formed on a semiconductor substrate as one chip and includes a current/voltage conversion circuit 1 for converting a current flowing into a piezoelectric element 10 into voltage, a resonance frequency detection circuit 2, a frequency variable oscillation circuit 3 for receiving a control signal from the resonance frequency detection circuit 2 and changing a frequency for outputting the control signal, and a piezoelectric element driving circuit 4 for driving the piezoelectric element. A frequency sweeping interval is fixed and a resonance frequency capable of sufficiently driving the piezoelectric element by sweeping only in one direction from a lower frequency to a higher frequency is detected. Differently from conventional circuits, a frequency capable of sufficiently driving the piezoelectric element can be adjusted by one step. By suppressing a circuit scale, the adjustment time of a drive frequency can be shortened. |
