| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrasonic motor drive circuit with can prevent generation of surge current and oscillation at high frequencies, at a low cost. SOLUTION: An A-phase amplifier circuit 42 of this drive circuit is provided with a transformer 100. The mid point of a primary-side coil 100A of the transformer 100 is connected by a power line 84. One end of the primary-side coil 100A is connected to the drain of a MOSFET 90, and the other end is connected to that of a MOSFET 92. The sources of the MOSFETs 90, 92 are grounded via ferrite beads 91, 93 respectively. When a switching signal A1 is turned off, although a surge voltage is generated in the drain of the MOSFET 90 and the MOSFET 90 oscillates at high frequencies, however, these phenomena can be restrained by the ferrite beads 91. |
