Device, method and system for controlling rotation speed of motor

摘要

The present application discloses a device, method and system for controlling a rotation speed of a motor. The device includes: a reference voltage generating module generating a reference voltage; a PWM signal converting module converting a PWM signal into a voltage signal; a first comparator outputting a first level or a second level; a first switching element having a control terminal connected with an output terminal of the first comparator and a first terminal input with a first signal, and being turned on when receiving the second level and being turned off when receiving the first level; a follower having an input terminal connected with the PWM signal converting module; and a control signal outputting terminal outputting the first signal or the voltage signal. The device, method and system are capable of controlling the rotation speed of the motor to jump at a specific duty cycle.

主权项

1. A device for controlling a rotation speed of a motor, comprising:
a reference voltage generating module configured to generate a reference voltage; a Pulse Width Modulation (PWM) signal converting module configured to convert a PWM signal into a voltage signal corresponding to a duty cycle of the PWM signal; a first comparator having a positive terminal connected with the reference voltage generating module and a negative terminal connected with the PWM signal converting module, and configured to output a first level when a voltage of the voltage signal converted from the PWM signal is less than or equal to the reference voltage, and to output a second level when the voltage of the voltage signal converted from the PWM signal is greater than the reference voltage; a first switching element having a control terminal connected with an output terminal of the first comparator and a first terminal input with a first signal, and configured to be turned on when receiving the second level output from the output terminal of the first comparator so as to enable a connection between the first terminal and a second terminal of the first switching element, and to be turned off when receiving the first level output from the output terminal of the first comparator; a follower having an input terminal connected with the PWM signal converting module; and a control signal outputting terminal connected with the second terminal of the first switching element and an output terminal of the follower, and configured to output the first signal received from the second terminal of the first switching element or the voltage signal which is converted from the PWM signal and is received from the follower to a motor control circuit; wherein when the first switching element is turned on, the motor control circuit is input with the first signal which makes the motor control circuit control the rotation speed of the motor to be zero or a predetermined speed; and when the first switching element is turned off, the motor control circuit is input with the voltage signal converted from the PWM signal to make the rotation speed of the motor be determined by the duty cycle of the PWM signal.