Abstract: A motor rotational speed control system and method having a duty cycle variable modulation mechanism is provided. The motor rotational speed control system is performed by the motor rotational speed control system including a motor rotational speed detector and a motor driver. When a rotational speed of a motor detected by the motor rotational speed detector is larger than or equal to a set rotational speed, the motor driver modulates duty cycles of a plurality of waveforms of an on-time signal, and modulates a duty cycle difference between the duty cycle of each of the plurality of waveforms and the duty cycle of a previous one or every other one of the plurality of waveforms in the on-time signal. The motor driver, according to the on-time signal, drives the motor such that the rotational speed of the motor is limited to be smaller than the set rotational speed.

Abstract: A motor driver having a motor abnormality detection mechanism is provided. A motor position detecting circuit detects a change in a state of a rotor of the motor switching between a plurality of magnetic pole positions to output a commutation signal. An abnormality determining circuit, according the commutation signal, determines a plurality of time intervals during which the rotor of the motor is switched to the plurality of magnetic pole positions respectively to output an abnormality detected signal. A rotational protection controller circuit outputs a rotation protecting signal to a motor driving circuit according to the abnormality detected signal. A motor driving circuit drives the motor according to the rotation protecting signal. When the abnormality detected signal received by the rotational protection controller circuit indicates that the motor abnormally rotates, the rotational protection controller circuit adjusts the rotation protecting signal outputted to the motor driving circuit.

Abstract: A motor driver using a motor magnetic pole reference controlling mechanism is provided. A motor position detecting circuit detects a rotor of a motor to determine a plurality of magnetic pole positions to which the rotor of the motor is switched respectively during a plurality of time intervals. A reference magnetic pole switching circuit selects one of the plurality of time intervals according to a change in rotational speed of the motor over time. The reference magnetic pole switching circuit uses the magnetic pole position to which the rotor of the motor is switched during the one of the plurality of time intervals as magnetic pole reference data. A motor driving circuit drives the motor according to the magnetic pole reference data from the reference magnetic pole switching circuit.

Abstract: A motor forward and reverse rotation detector and a motor driver having the motor forward and reverse rotation detector are provided. A rotor position detecting circuit detects a position of a rotor of a motor to output a commutation signal. A forward and reverse rotation detecting circuit detects a back electromotive force of the motor to output a back electromotive force detected signal. The forward and reverse rotation detecting circuit, according to a phase relationship and a phase difference between the back electromotive force detected signal and the commutation signal, determines which one of a forward direction and a reverse direction is a rotational direction of the motor to output a rotational direction detected signal. A motor driving circuit drives the motor according to the rotational direction detected signal.

Abstract: A motor driver using a motor magnetic pole reference controlling mechanism is provided. A motor position detecting circuit detects a rotor of a motor to determine a plurality of magnetic pole positions to which the rotor of the motor is switched respectively during a plurality of time intervals. A reference magnetic pole switching circuit selects one of the plurality of time intervals according to a change in rotational speed of the motor over time. The reference magnetic pole switching circuit uses the magnetic pole position to which the rotor of the motor is switched during the one of the plurality of time intervals as magnetic pole reference data. A motor driving circuit drives the motor according to the magnetic pole reference data from the reference magnetic pole switching circuit.

Abstract: A motor driver having a motor abnormality detection mechanism is provided. A motor position detecting circuit detects a change in a state of a rotor of the motor switching between a plurality of magnetic pole positions to output a commutation signal. An abnormality determining circuit, according the commutation signal, determines a plurality of time intervals during which the rotor of the motor is switched to the plurality of magnetic pole positions respectively to output an abnormality detected signal. A rotational protection controller circuit outputs a rotation protecting signal to a motor driving circuit according to the abnormality detected signal. A motor driving circuit drives the motor according to the rotation protecting signal. When the abnormality detected signal received by the rotational protection controller circuit indicates that the motor abnormally rotates, the rotational protection controller circuit adjusts the rotation protecting signal outputted to the motor driving circuit.

Abstract: A motor forward and reverse rotation detector and a motor driver having the motor forward and reverse rotation detector are provided. A rotor position detecting circuit detects a position of a rotor of a motor to output a commutation signal. A forward and reverse rotation detecting circuit detects a back electromotive force of the motor to output a back electromotive force detected signal. The forward and reverse rotation detecting circuit, according to a phase relationship and a phase difference between the back electromotive force detected signal and the commutation signal, determines which one of a forward direction and a reverse direction is a rotational direction of the motor to output a rotational direction detected signal. A motor driving circuit drives the motor according to the rotational direction detected signal.

Abstract: An overvoltage protecting system and method of a motor pre-driver are provided. An overvoltage protecting circuit compares a first reference voltage with a common voltage inputted to a single phase motor to output a first comparison signal. When a controller circuit determines that the common voltage is higher than the first reference voltage according to the first comparison signal, the controller circuit turns off a first high-side switch and a second high-side switch, and turns on the first low-side switch and the second low-side switch, during a phase time of a phase transition signal of the single phase motor. After the phase time ends, the controller circuit alternately turns on the first low-side switch and the second low-side switch according to a level of the phase transition signal.

Abstract: A brake control system of a motor is provided. When a control circuit intends to brake the motor, the control circuit controls a driver circuit to turn off a first high-side switch and a second high-side switch, and to fully turn on the first low-side switch and the second low-side switch, for a period of time. Then, the control circuit controls the driver circuit to turn off one of the first low-side switch and the second low-side switch, and to continually turn on the other one of the first low-side switch and the second low-side switch, for a period of time. Then, the control circuit controls the driver circuit to turn off the other one of the first low-side switch and the second low-side switch, and to turn on the one of the first low-side switch and the second low-side switch, for a period of time.

Abstract: A brake control system of a motor is provided. When a control circuit intends to brake the motor, the control circuit controls a driver circuit to turn off a first high-side switch and a second high-side switch, and to fully turn on the first low-side switch and the second low-side switch, for a period of time. Then, the control circuit controls the driver circuit to turn off one of the first low-side switch and the second low-side switch, and to continually turn on the other one of the first low-side switch and the second low-side switch, for a period of time. Then, the control circuit controls the driver circuit to turn off the other one of the first low-side switch and the second low-side switch, and to turn on the one of the first low-side switch and the second low-side switch, for a period of time.

Abstract: A current limit protecting system and method of a motor pre-driver are provided. A current limiting circuit detects a current of a resistor that is connected to a motor, and then compares the current of the resistor with a current threshold to output a current comparing signal. When a controller circuit determines that the current of the resistor is larger than the current threshold according to the current comparing signal, and a working period of a first signal of a first node or a working period of a second signal of a second node of the motor reaches a preset value, a first high-side switch and a second high-side switch are turned off, and a first low-side switch and a second low-side switch are alternately turned on. As a result, a temperature of the motor generally reduces.

Abstract: A motor output stabilizing circuit and a method are provided. A sensor senses a positive voltage and a negative voltage that are generated with a change in magnetic field strength of a motor of which a rotor is rotating. A comparator compares the positive voltage with the negative voltage to output a Hall signal. An average counter records a first time during which the positive voltage is higher than the negative voltage and a second time during which the negative voltage is higher than the positive voltage, according to the Hall signal. The average counter then averages the first time and the second time to output an averaged time signal. A motor controller circuit controls a motor driver circuit to drive the motor according to the averaged time signal, such that the motor outputs a constant current.

Abstract: A current limit protecting system and method of a motor pre-driver are provided. A current limiting circuit detects a current of a resistor that is connected to a motor, and then compares the current of the resistor with a current threshold to output a current comparing signal. When a controller circuit determines that the current of the resistor is larger than the current threshold according to the current comparing signal, and a working period of a first signal of a first node or a working period of a second signal of a second node of the motor reaches a preset value, a first high-side switch and a second high-side switch are turned off, and a first low-side switch and a second low-side switch are alternately turned on. As a result, a temperature of the motor generally reduces.

Abstract: An overvoltage protecting system and method of a motor pre-driver are provided. An overvoltage protecting circuit compares a first reference voltage with a common voltage inputted to a single phase motor to output a first comparison signal. When a controller circuit determines that the common voltage is higher than the first reference voltage according to the first comparison signal, the controller circuit turns off a first high-side switch and a second high-side switch, and turns on the first low-side switch and the second low-side switch, during a phase time of a phase transition signal of the single phase motor. After the phase time ends, the controller circuit alternately turns on the first low-side switch and the second low-side switch according to a level of the phase transition signal.

Abstract: A motor output stabilizing circuit and a method are provided. A sensor senses a positive voltage and a negative voltage that are generated with a change in magnetic field strength of a motor of which a rotor is rotating. A comparator compares the positive voltage with the negative voltage to output a Hall signal. An average counter records a first time during which the positive voltage is higher than the negative voltage and a second time during which the negative voltage is higher than the positive voltage, according to the Hall signal. The average counter then averages the first time and the second time to output an averaged time signal. A motor controller circuit controls a motor driver circuit to drive the motor according to the averaged time signal, such that the motor outputs a constant current.

Abstract: A motor driving device includes a first hysteresis comparator, a second hysteresis comparator, a logic circuit, a control unit, and an inverter circuit. The logic circuit receives a start signal or a start completion signal to output the first output signal as a commutation signal according to the start signal, or to output the second output signal as the commutation signal according to the start completion signal, clamps the second output signal by the first output signal, stops outputting the commutation signal after the potential state of the commutation signal is changed, and unclamps the second output signal with the first output signal and outputs the commutation signal in response to a difference voltage between the first input signal and the second input signal being greater than a positive value of the first hysteresis voltage or less than a negative value of the first hysteresis voltage.

Abstract: A motor driving device includes a first hysteresis comparator, a second hysteresis comparator, a logic circuit, a control unit, and an inverter circuit. The logic circuit receives a start signal or a start completion signal to output the first output signal as a commutation signal according to the start signal, or to output the second output signal as the commutation signal according to the start completion signal, clamps the second output signal by the first output signal, stops outputting the commutation signal after the potential state of the commutation signal is changed, and unclamps the second output signal with the first output signal and outputs the commutation signal in response to a difference voltage between the first input signal and the second input signal being greater than a positive value of the first hysteresis voltage or less than a negative value of the first hysteresis voltage.