| 摘要 |
PURPOSE: To make it possible to reduce the size and cost of a microcomputer without using D/A converter by changing the pulse width of output pulses of a predetermined frequency, converting the duty to a voltage value, oscillating with the frequency corresponding to an output voltage, and dividing and phase- shifting the alternating voltage of its output frequency. CONSTITUTION: In this drive circuit, a PWM signal of a predetermined frequency generated from a micro-computer 1 is input to LPF 2, only low frequency components are passed to LPF 2, and a frequency voltage corresponding to the output voltage of LPF 2 is output by a voltage controlled oscillator 3. Its frequency voltage is divided by a frequency divider/phase shifter 4, and a square wave having a phase difference of μ/2 is output. Its outputted two- phase signal is amplified by power amplifiers 5 and 6 and applied to a vibration wave motor 9 through matching coils 7 and 8; then a pulse disc 10 is rotated together with the vibration wave motor 9 and this is detected by a photo- interrupter 11, the detected signal is amplified by a detecting circuit 12 and converted to a digital signal and then input to the micro-computer 1, thereby controlling the frequency of an AC voltage of the vibration wave motor 9. Therefore, the size of the micro-computer can be made smaller. |
