| 摘要 |
PROBLEM TO BE SOLVED: To obtain a motor drive for a motor driving a portable disc media requiring low power consumption and highly accurate rotation by obtaining a motor current corresponding to an input signal. SOLUTION: A voltage corresponding to the current being supplied to the winding of a motor is inputted to an input signal 12, in order to set the voltage at one end of a comparator 20 having the other end connected with a detection resistance 11 and the voltage thereof is varied depending on the motor current. When the voltage of the detection resistance 11 increases under a conducting state of output transistors 5-7 to exceed the voltage of the input signal 12, a comparator 20 is operated to reset a flip-flop 22 and a PWM control circuit 13 brings the output transistors 5-7 into a nonconducting state, thus decreasing the current flowing through the motor windings 24-26. Since the peak level of current flowing through the motor winding 24-26 is controlled by the input signal 12, a motor current corresponding to the input signal 12 can be obtained. |
