Abstract: A power converter having a voltage difference control mechanism includes a high-side switch, a low-side switch, a high-side off-state driver circuit, a high-side on-state driver circuit, a high-side off-state driver circuit and a high-side voltage difference modulating circuit. The high-side on-state driver circuit switches the high-side switch from an off-state to an on-state. The high-side voltage difference modulating circuit outputs a floating voltage to a first power input terminal of the high-side off-state driver circuit according to an output voltage of the output node. The high-side off-state driver circuit uses the floating voltage to switch the high-side switch from the on-state to the off-state such that a voltage difference between the floating voltage and the output voltage falls within a target voltage range.

Abstract: A motor driver for starting up a motor having any resistance is provided. The motor driver outputs a motor startup signal to the motor according to an initial startup duty cycle, senses a current value of a current signal of the motor multiple times, compares the current value of the motor that is sensed for multiple times with a reference current value and accordingly sets a plurality of pulse waves of a pulse width modulation signal. Then, the motor driver detects duty cycles of the pulse waves of the pulse width modulation signal as startup detection duty cycles. Then, the motor driver outputs a motor startup signal to the motor according to the startup detection duty cycles.

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 circuit having a dynamic duty cycle modulation mechanism is provided. The motor driver circuit includes a magnetic field change sensing circuit, a control circuit, a driver circuit and an output stage circuit. The magnetic field change sensing circuit senses a plurality of voltages that are generated with a change in a magnetic field caused by a motor whose rotor is rotating to output a commutation signal. The control circuit sets a plurality of control duty cycles according to the commutation signal. The control circuit outputs a control duty cycle signal according to each of the control duty cycles. The driver circuit outputs a driving signal according to the control duty cycle signal. The output stage circuit operates to output a plurality of output stage signals to the motor according to the driving signal.

Abstract: A motor driver having an overcurrent protection mechanism is provided. The motor driver includes an output stage circuit and a motor driving circuit. The output stage circuit includes a plurality of high-side switches, a plurality of low-side switches and a motor driving circuit. When an overcurrent event occurs in the output stage circuit according to a parameter of any one of the plurality of low-side switches, the motor driving circuit turns off all of the plurality of high-side switches. When all of the high-side switches are turned off and the overcurrent event is still occurring in the output stage circuit, the motor driving circuit turns off all of the plurality of low-side switches and continually turns off the high-side switches.

Abstract: A motor starting circuit having a dead time setting mechanism is provided. The motor starting circuit includes a rotational speed detection circuit, a start-up commutation selector circuit, a control circuit, a driver circuit and an output stage circuit. The rotational speed detection circuit detects a rotational speed of a motor. The start-up commutation selector circuit determines whether or not to set a dead time within a motor start-up time interval to output a commutation instructing signal according to the rotational speed of the motor. The control circuit controls the driver circuit to drive the output stage circuit so as to start up the motor according to the commutation instructing signal.

Abstract: A motor driver for starting up a motor having any resistance is provided. The motor driver outputs a motor startup signal to the motor according to an initial startup duty cycle, senses a current value of a current signal of the motor multiple times, compares the current value of the motor that is sensed for multiple times with a reference current value and accordingly sets a plurality of pulse waves of a pulse width modulation signal. Then, the motor driver detects duty cycles of the pulse waves of the pulse width modulation signal as startup detection duty cycles. Then, the motor driver outputs a motor startup signal to the motor according to the startup detection duty cycles.

Abstract: A motor driver improving resonance noise caused by a motor is provided. The motor driver sets one or more duty cycle threshold ranges. When a duty cycle of each waveform of a duty cycle input signal does not fall within the one or more duty cycle threshold ranges, the motor driver directly drives the motor according to the duty cycle input signal. When the duty cycle of any waveforms of the duty cycle input signal falls within the one or more duty cycle threshold ranges, the motor driver adjusts the duty cycles of some waveforms of the duty cycle input signal within specified time such that the duty cycles of at least two of the plurality of waveforms of the duty cycle input signal are different from each other, and drives the motor according to the adjusted duty cycle input signal.

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 starting circuit having a dead time setting mechanism is provided. The motor starting circuit includes a rotational speed detection circuit, a start-up commutation selector circuit, a control circuit, a driver circuit and an output stage circuit. The rotational speed detection circuit detects a rotational speed of a motor. The start-up commutation selector circuit determines whether or not to set a dead time within a motor start-up time interval to output a commutation instructing signal according to the rotational speed of the motor. The control circuit controls the driver circuit to drive the output stage circuit so as to start up the motor according to the commutation instructing signal.

Abstract: A power converter having a charge pump frequency switching control mechanism is provided. In the power converter, frequencies of a plurality of pulse waves of a clock signal are determined, according to a level of a high-side control signal outputted to a control terminal of a high-side switch from a control circuit or a voltage of the control terminal (and a voltage of a second terminal) of the high-side switch. In the power converter, a charge pump supplies power to a high-side driver circuit at the frequencies of the clock signal, and the high-side driver circuit uses the power from the charge pump to drive the high-side switch and to pull up the voltage of the control terminal of the high-side switch.

Abstract: A motor driver having a temperature sensing mechanism is provided. A control circuit determines a time for outputting a controlling signal according to a pulse-width modulation signal received from an external pulse-width modulation circuit. A driving circuit outputs a driving signal according to the controlling signal. An output stage circuit operates according to the driving signal to output an output stage signal to a motor to drive the motor to rotate. In a temperature sensing mode, a thermal sensor circuit senses a temperature inside the motor driver to output a temperature sensing signal. An external system circuit determines whether or not the motor driver causes overheating to the motor when being adapted to the motor according to the temperature sensing signal, and evaluates whether or not the motor driver is applicable to the motor.

Abstract: A motor driver of setting pulse width modulation at commutation time points of a motor is provided. A commutation control circuit outputs a phase control signal and a commutation starting signal according to a preset phase angle and a commutation signal of the motor. A pulse width modulation calculating circuit determines a starting time point of each of a plurality of cycles of a pulse width modulation signal according to the commutation starting signal. The pulse width modulation calculating circuit determines time of each of the plurality of cycles of the pulse width modulation signal according to the phase control signal. The pulse width modulation calculating circuit determines widths of a plurality of pulse waves of the pulse width modulation signal according to a target rotational speed of the motor. A motor driver circuit drives the motor according to the pulse width modulation signal.

Abstract: A motor driver circuit having a reverse current detection mechanism is provided. The motor driver circuit includes a reverse current detector circuit, a control circuit, a driver circuit and an output stage circuit. The reverse current detector circuit detects a current flowing through a motor within a preset time interval to output a current detected signal. The control circuit determines whether or not the detected current is a reverse current to output a control signal according to the current detected signal. The driver circuit outputs a driving signal according to the control signal. The output stage circuit operates to output an output-stage signal to the motor according to the driving signal. The motor rotates according to the output-stage signal.

Abstract: A power converter having a multi-stage high-side driving mechanism is provided. A control circuit outputs a first high-side control signal. A high-side driving circuit, according to the first high-side control signal and a first input voltage signal, outputs a first stage high-side driving signal to a control terminal of a high-side switch. As a result, a voltage of the control terminal of the high-side switch is pulled up to a first stage voltage from zero. Then, the control circuit outputs a second high-side control signal. A charge pump outputs a charging signal. The high-side driving circuit, according to the second high-side control signal and the charging signal, outputs a second stage high-side driving signal to the control terminal of the high-side switch. As a result, the voltage of the control terminal of the high-side switch is pulled up from the first stage voltage to a target voltage.

Abstract: A power converter having a charge pump frequency switching control mechanism is provided. In the power converter, frequencies of a plurality of pulse waves of a clock signal are determined, according to a level of a high-side control signal outputted to a control terminal of a high-side switch from a control circuit or a voltage of the control terminal (and a voltage of a second terminal) of the high-side switch. In the power converter, a charge pump supplies power to a high-side driver circuit at the frequencies of the clock signal, and the high-side driver circuit uses the power from the charge pump to drive the high-side switch and to pull up the voltage of the control terminal of the high-side switch.

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, a control method of the motor driver, and a motor driving system are provided. The motor driver includes a rotation information pin, an analog detecting circuit and a mode switching circuit. The rotation information pin is configured to receive a reference signal. The analog detecting circuit and the mode switching circuit are respectively and electrically connected to the rotation information pin and the analog detecting circuit. The analog detecting circuit determines whether the reference signal is an analog signal, and the motor driver is maintained in a master mode when the reference signal does not belong to the analog signal. The mode switching circuit determines whether the reference signal is a noise when the reference signal is the analog signal. The mode switching circuit switches the motor driver from the master mode to a slave mode when the reference signal is not the noise.

Abstract: A motor driver having a temperature sensing mechanism is provided. A control circuit determines a time for outputting a controlling signal according to a pulse-width modulation signal received from an external pulse-width modulation circuit. A driving circuit outputs a driving signal according to the controlling signal. An output stage circuit operates according to the driving signal to output an output stage signal to a motor to drive the motor to rotate. In a temperature sensing mode, a thermal sensor circuit senses a temperature inside the motor driver to output a temperature sensing signal. An external system circuit determines whether or not the motor driver causes overheating to the motor when being adapted to the motor according to the temperature sensing signal, and evaluates whether or not the motor driver is applicable to the motor.

Abstract: A motor driver using a correcting mechanism on a sensed motor position is provided. A rotor position detector circuit senses a position of a rotor of a motor to output a commutation signal. A back electromotive force detector circuit detects a back electromotive force signal of the motor. An actual phase difference calculator circuit calculates a phase difference between the back electromotive force signal and the commutation signal as an actual phase difference. An error phase angle calculator circuit calculates a difference between the actual phase difference and a reference phase difference as an error phase angle. A motor driving circuit corrects the commutation signal according to the error phase angle. The motor driving circuit determines the position of the rotor of the motor to drive the motor according to the corrected commutation signal.