| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem associated with conventional stepper motor drivers: the two-phase excitation vectorial sum current value is larger than the one-phase excitation current value and an uneven torque is produced between one-phase excitation timing and two-phase excitation timing, so that smooth rotational driving is not performed. SOLUTION: In a stepper motor driver, a number-of-phases determination circuit 30 determines whether or not it is a timing to pass an excitation current through two phases based on an excitation phase signal 20a from an excitation sequence generation circuit 20. When a timing for allowing an excitation current to pass through the two phases is detected based on a number-of-phases signal 30a from the number-of-phases determination circuit 30, a current value setting circuit 40 varies the excitation current passed through the winding by a drive circuit 10 so that the two-phase excitation vectorial sum current value becomes equal to the one-phase excitation current value. COPYRIGHT: (C)2010,JPO&INPIT |
