Abstract: An apparatus for starting a direct current brushless motor and a method thereof are provided. The direct current brushless motor comprises a plurality of windings. The control apparatus comprises a sense amplifier, a differential circuit, and a control circuit. The sense amplifier is configured to detect a first back electromotive force of a non-electrified first winding. The differential circuit is configured to calculate a differential value of the first back electromotive force. The control circuit is configured to provide a current to two of the windings and to switch the current to another two of the windings to start the direct current brushless motor.

Abstract: A starting apparatus for a direct current (DC) brushless motor and a method thereof are provided. The DC brushless motor comprises a plurality of windings presenting a joint connection via a common connection. The starting apparatus provides current to two of the three windings and rotates the DC brushless motor to obtain a Back Electro-Motive Force (BEMF) from the floating winding. Then, the starting apparatus provides a current to another two windings to operate the motor according to the variation of BEMF induced by the swing of the motor when it rotates to a static equilibrium point.

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.

Abstract: The present invention discloses a brushless dc motor driver circuit capable of reducing vibration or shock noise and a method thereof. The brushless dc motor driver circuit of the present invention comprises a Time-Voltage Digital/Analog Converter. The Time-Voltage Digital/Analog Converter further comprises: at least one magnetic field detecting circuit, at least one counter, and a signal processor. The Time-Voltage Digital/Analog Converter is connected to a driver circuit of a brushless dc motor and detects the periodically varying magnetic field of the brushless dc motor. Based on the rising time and the falling time of the preceding magnetic field variation, the Time-Voltage Digital/Analog Converter calculates the elapsed time from the current phase-change point and generates a linearly rising signal and a linearly falling signal. Then, those two sets of analog signals are used to drive the brushless dc motor. Thereby, the vibration or shock noise of the brushless dc motor is reduced.

Abstract: A period adjustment circuit of disconnection and restart IC comprises a second capacitor, which is connected to a resistor and a transistor connected in parallel. One end of the resistor is connected between the disconnection and restart IC and the first capacitor. When lockup of a fan motor occurs, in addition that an IC current source charges the first capacitor, the second capacitor also charges the first capacitor via the resistor until the voltage of the first capacitor reaches a disconnection voltage. The IC then enters into the disconnection state, and the voltages of the two capacitors are equal so that the second capacitor no longer charges the first capacitor. Next, the IC current source simultaneously charges the first and second capacitors until the voltage of the first capacitor reaches a system reset voltage. The first capacitor is then discharged to a restart voltage by the IC.