1. Technical Field
The present invention generally relates to a motor speed control circuit, more particularly, to a motor speed control circuit and a control method thereof, capable of adjusting a motor speed according to a plurality of motor speed curves.
2. Description of Related Art
With the development of technology, motors to run fans to cool computers have become indispensable electronic devices in this information society. Common motors such as direct-current (DC) motors, alternating-current (AC) motors, stepper motors, etc., have been widely used to drive the fans.
For a general motor, the higher the voltage supplied to the motor, the higher the rotational speed of the motor. The lower the voltage supplied to the motor, the lower the rotational speed of the motor. In other words, the voltage supplied to the motor is proportional to the rotational speed of the motor.
However, as the development of motor-based products gets more and more diverse, the design of motors has to be changed. For example, a general computer and a power-saving computer are equipped with different motors operating according to different motor speed curves. The motor installed in the general computer starts to operate upon receiving the voltage, while the motor installed in the power-saving computer starts to operate after the input voltage increases to a predetermined value.
Therefore, there is a need in providing a motor control circuit, capable of adjusting a motor speed curve based on different products, to drive the motor to rotate.