MOTOR DRIVE CIRCUIT
First Claim
1. A motor drive circuit comprising:
- a drive voltage generation circuit generating a drive voltage corresponding to a target rotation speed of a motor;
a first pulse generation circuit generating a first pulse signal having a first logic level and a second logic level, a duty ratio of the first logic level of the first pulse signal being configured to increase as the drive voltage increases;
a second pulse generation circuit generating a second pulse signal having the first logic level and the second logic level, a duty ratio of the first logic level of the second pulse signal being different from the duty ratio of the first pulse signal; and
a drive control circuit supplying a drive current to a coil of the motor at the duty ratio of the second pulse signal so as to start a rotation of the motor that is not rotating and supplying a drive current to the coil at the duty ratio of the first pulse signal after a predetermined time from the start of the rotation of the motor in response to a rotation signal corresponding to the rotation of the motor.
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Accused Products
Abstract
The invention provides a motor with a low speed start function and a soft start function. The motor includes a first pulse generation circuit generating a first pulse signal of which a first duty ratio of one of logic levels is increased as a drive voltage corresponding the target rotation speed of the motor is increased, a second pulse generation circuit generating a second pulse signal of which a second duty ratio of one of logic levels is different from the first duty ratio, and a drive control circuit supplying a drive current to a motor coil at the second duty ratio in order to start the rotation of the motor that is stopping and supplying a drive current to the motor coil at the first duty ratio after a predetermined time passes from the start of the rotation of the motor in response to a rotation signal corresponding to the rotation of the motor.
30 Citations
4 Claims
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1. A motor drive circuit comprising:
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a drive voltage generation circuit generating a drive voltage corresponding to a target rotation speed of a motor; a first pulse generation circuit generating a first pulse signal having a first logic level and a second logic level, a duty ratio of the first logic level of the first pulse signal being configured to increase as the drive voltage increases; a second pulse generation circuit generating a second pulse signal having the first logic level and the second logic level, a duty ratio of the first logic level of the second pulse signal being different from the duty ratio of the first pulse signal; and a drive control circuit supplying a drive current to a coil of the motor at the duty ratio of the second pulse signal so as to start a rotation of the motor that is not rotating and supplying a drive current to the coil at the duty ratio of the first pulse signal after a predetermined time from the start of the rotation of the motor in response to a rotation signal corresponding to the rotation of the motor. - View Dependent Claims (2, 3, 4)
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Specification