Startup control circuit of drive circuit

摘要

Startup of motor is reliably executed and sonic noise is reduced. A control circuit controls a selector to apply control to output a full-drive waveform at startup and then output a PWM modulation waveform. The full-drive waveform which is an alternating waveform in which positive and negative are inverted at 180° is output. Then, the PWM drive waveform is selected.

主权项

1. A startup control circuit of a drive circuit which controls driving of a motor at startup, the startup control circuit comprising:
a full-drive waveform outputting circuit which outputs a full-drive waveform which is an alternating waveform in which positive and negative are inverted at 180°; a limited drive waveform outputting circuit which outputs a limited drive waveform in which a predetermined drive stop period is provided at a time when the positive and the negative are inverted; a PWM circuit which obtains a PWM drive waveform by applying pulse-width modulation to the limited drive waveform; a selector which selects one of the full-drive waveform and the PWM drive waveform; and a control circuit which controls the selector to apply control to output the full-drive waveform at startup and then output the PWM drive waveform.