| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor driver which has an automatically switching function of a resistance value of a variable resistor for automatically abolishing an offset generated owing to a temperature change and which simplifies a function of automatically switching the resistance value of this variable resistor. <P>SOLUTION: The motor driver includes a counterelectromotive voltage detecting circuit 12 which has an AD converter 14 for converting an output from a differential amplifier A2 into a digital signal, and an offset arithmetic circuit 15 for setting a resistance value of a variable resistor R2 based on an output from the AD converter 14. The offset arithmetic circuit 15 sets the resistance value of the variable resistor R2, based on a difference between an output from the AD converter 14 when the drive current flowing to a motor coil L is "0" and an output from the AD converter 14 when the drive current flowing to the motor coil L is set to a predetermined value. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
