Abstract: A method of the Pulse Amplitude Modulation for the Sensorless Brushless motor, which includes a start-up circuit, a phase detect circuit, a phase commutation circuit, a driving circuit, BEMF detection circuit, and frequency detector, utilizes the control signal of the phase commutation circuit to control the driving circuit so as to drive the outer motor coil and detect the control signal for the driving motor driving circuit by a detection circuit. The motor system can be controlled to reduce the discharge speed to avoid the motor driving circuit shutdown and further speed up the start-up time for the next charging period of the motor driving circuit to achieve the effect of low speed rotation and power saving.

Abstract: An anti-noise method for the Direct Current Brushless motor System, which includes a startup circuit, phase detective circuit, motor phase commutation circuit, driving circuit, BEMF detective circuit, and frequency detector, utilizes the BEMF detective circuit to detect the BEMF induced from the coils of the outer motor, and utilizes the sampled voltage phase to determine rotation speed and phase of the external motor by the phase detection circuit and frequency detector. Further, the sampling voltage of the BEMF detection circuit is feedback controlled by the frequency detector, utilized to keep good BEMF to noise ratio, and avoids the BEMF sampling error from the system.

Abstract: A method of the Pulse Amplitude Modulation for the Sensorless Brushless motor, which includes a start-up circuit, a phase detect circuit, a phase commutation circuit, a driving circuit, BEMF detection circuit, and frequency detector, utilizes the control signal of the phase commutation circuit to control the driving circuit so as to drive the outer motor coil and detect the control signal for the driving motor driving circuit by a detection circuit. The motor system can be controlled to reduce the discharge speed to avoid the motor driving circuit shutdown and further speed up the start-up time for the next charging period of the motor driving circuit to achieve the effect of low speed rotation and power saving.

Abstract: An anti-noise method for the Direct Current Brushless motor System, which includes a startup circuit, phase detective circuit, motor phase commutation circuit, driving circuit, BEMF detective circuit, and frequency detector, utilizes the BEMF detective circuit to detect the BEMF induced from the coils of the outer motor, and utilizes the sampled voltage phase to determine rotation speed and phase of the external motor by the phase detection circuit and frequency detector. Further, the sampling voltage of the BEMF detection circuit is feedback controlled by the frequency detector, utilized to keep good BEMF to noise ratio, and avoids the BEMF sampling error from the system.