Method for controlling a direct current brushless motor, and control circuit
AssigneeFeeling Technology Corp.
InventorsHsuan-Chuan Chen, Wen-Jung Su
Life of this patent
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Abstract
A method for controlling a direct current (DC) brushless motor, and a control circuit thereof are provided. The DC brushless motor is sensorless. In response to a digital output signal that is applied to drive the direct current brushless motor, detection of a back electromotive force (BEMF) is ceased in a predetermined time interval, so as to avoid detecting erroneous BEMF and keep normal operation of the direct current brushless motor.
Claims19
A method for controlling a direct current (DC) brushless motor, comprising the steps of:
- (a) receiving a pulse width modulation (PWM) signal and generating a digital output signal synchronous with the PWM signal to drive the DC blushless motor;
- (b) detecting a back electromotive force (BEMF) generated in accordance with operation of the DC brushless motor;
- (c) continuously driving the DC blushless motor in response to the BEMF;
- (d) generating a mask signal when the digital output signal changes a status thereof;
- and
- (e) ceasing detecting the BEMF in the predetermined time interval in response to the mask signal.
A control circuit for controlling a direct current (DC) brushless motor, the control circuit comprising:
- an output circuit, coupled to a coil of the DC brushless motor, in which the output circuit receives a pulse width modulation (PWM) signal and generates a digital output signal synchronous with the PWM signal for driving the DC brushless motor;
- a pulse generating circuit, coupled to the output circuit, in which the pulse generating circuit is adapted to generate and provide a serial square wave signal to the output circuit for generating the digital output signal;
- a detecting circuit, coupled to the pulse generating circuit, in which the detecting circuit is adapted to detect a back electromotive force (BEMF) generated in accordance with operation of the DC brushless motor and to generate a detection signal so that the pulse generating circuit generates the serial square wave signal in response to the detection signal;
- and
- a mask circuit, coupled to the pulse generating circuit, in which the mask circuit is adapted to generate a mask signal in response to an external PWM signal so that the pulse generating circuit generates the serial square wave signal in response to the mask signal in a predetermined time interval, wherein the external PWM signal is synchronous with the PWM signal.
A control circuit for controlling a direct current (DC) brushless motor, the control circuit comprising:
- a first terminal and a second terminal both coupled to the DC brushless motor;
- a third terminal receiving a pulse width modulation (PWM) signal;
- a bus;
- an output circuit, coupled to the bus, and generating a digital output signal synchronous with the PWM signal in response to the PWM signal, the digital output signal is coupled to the DC brushless motor to a coil thereof and adapted to drive the DC brushless motor;
- a pulse generating circuit, coupled to the output circuit, and adapted to generate and provide a serial square wave signal to the output circuit for generating the digital output signal;
- a detecting circuit, coupled to the first terminal, the second terminal and the pulse generating circuit, detecting a back electromotive force (BEMF) generated in accordance with operation of the DC brushless motor via the first terminal and the second terminal, generating a detection signal in response to the BEMF, in which the pulse generating circuit generates the serial square wave signal in response to the detection signal;
- and
- a mask circuit coupled to the third terminal and the pulse generating circuit, generating a mask signal in response to the PWM signal, in which the pulse generating circuit generates the serial square wave signal in response to the mask signal in a predetermined time interval.
Dependencies are inferred from the claim text.