| 摘要 |
<P>PROBLEM TO BE SOLVED: To secure a soft start function while a motor can be started at low speed. <P>SOLUTION: A motor drive circuit includes: a pulse generating circuit generating a first pulse signal whose duty ratio of one logical level is a first duty ratio; and a drive control circuit supplying a driving current to a motor coil at the first duty ratio when rotation is started from a state where the motor stops based on a rotation signal corresponding to rotation of the motor and supplying the driving current to the motor coil at a second duty ratio of a second pulse signal whose second duty ratio of one logical level becomes high in accordance with target rotational speed of the motor after the motor starts the rotation. The pulse generating circuit generates the first pulse signal of the first duty ratio different from the second duty ratio. <P>COPYRIGHT: (C)2012,JPO&INPIT |
