Abstract: The present invention discloses a motor driving circuit for driving a motor, including an electrostatic discharge diode, having an input port and an output port coupled to a first DC power supply, a pulse width modulation source coupled to the input port of the electrostatic discharge diode to generate a pulse width modulation signal, and a driving module including a voltage detecting module comparing the pulse width modulation signal with a voltage of the output port of the electrostatic discharge diode to generate a voltage comparison result, a lock/restart module generating a shut-down signal according to the voltage comparison result, a control module generating a control signal according to the shut-down signal, and a bridge circuit switching the motor on or off by turning on or turning off an up-bridge circuit and a down-bridge circuit according to the control signal.

Abstract: A rotation speed control circuit for controlling a rotation speed of a fan includes: a rotation speed detector, for generating a rotation speed voltage according to a rotation speed signal corresponding to the rotation speed; a sample and hold element, coupled to the rotation speed detector, for sampling and storing the rotation speed voltage; an error amplifier, coupled to the sample and hold element, for controlling a voltage of a filter capacitor according to the rotation speed voltage and a reference voltage, to adjust an error voltage; and a pulse width modulation signal generator, coupled to the filter capacitor, for generating a pulse width modulation signal according to the error voltage and a triangle wave.

Abstract: An over voltage protection circuit is disclosed. The over voltage protection circuit comprises an input end, coupled to an input power, for receiving an input voltage provided by the input power; and a driving module, coupled between the input end and a ground end, for generating a discharging current when the input voltage is larger than a predefined voltage, to reduce the input voltage to the predefined voltage.

Abstract: The present invention discloses a start-up circuit for a motor driving IC. The activation circuit includes a determination unit, for generating a determination result indicating an operating mode of the motor driving IC according to an external pulse width modulation signal, and an output unit, for outputting an activation signal according to the determination result and a pulse width modulation activation signal. A duty of the pulse width modulation activation signal is greater than a duty of the external pulse width modulation signal.

Abstract: The present invention discloses a pulse width modulation driving IC. The pulse width modulation driving IC includes a first pin, for receiving a first signal, a second pin, for receiving a second signal, a comparing unit, for comparing the first signal with a reference voltage, to generate a comparison result indicating a operating mode of the pulse width modulation driving IC, and an output unit, for outputting a pulse width modulation output signal according to the first signal, the second signal and the comparison result.

Abstract: Power control circuit with reducing noise and switching loss includes a first gate driver for driving a first switch, an additional gate driver for driving the first switch, and a managing circuit for controlling the first and the additional gate driver to drive the first switch according to a switching signal and turning off the additional gate driver according to a switching voltage on a first end of the first switch, wherein the first end of the first switch is coupled to a load, second end of the first switch is coupled to an input power source, a third end of the first switch is coupled to the first and the additional gate drivers.

Abstract: A motor driving method for driving a direct-current (DC) motor, designed for avoiding a reverse current induced by the Back Electromotive Force (BEMF), includes providing a driver circuit for driving the DC motor; comparing a signal level of a terminal of the DC motor and a predetermined voltage value to produce a comparing result; and controlling a specific lower gate switch to avoid the occurrence of a reverse current of the DC motor according to the comparing result.

Abstract: A control method of a current limit of a DC motor includes generating a reference voltage according to a preset current limit value of a DC motor; comparing the reference voltage with the voltage drop of a power control switch which drives the DC motor to generate a compare result; and controlling the power delivered to the DC motor according to the compare result in order to limit the current of the DC motor.

Abstract: A sensorless method for starting a three-phase brushless direct-current motor includes generating a start-up control signal, a start mode selection signal, and a control signal commutation period; switching to a start mode according to the start mode selection signal; implementing a position aligning procedure according to the start-up control signal and the control signal commutation period; detecting a zero crossing point of back electromotive forces during each control signal commutation period; outputting a sensorless mode selection signal while detecting the zero crossing points of the back electromotive forces during consecutive control signal commutation periods; switching to a sensorless mode according to the sensorless mode selection signal; and detecting a zero crossing point of back electromotive forces in the sensorless mode to determine a starting result of the three-phase brushless direct-current motor.

Abstract: A rotation speed control circuit for controlling a rotation speed of a fan includes: a rotation speed detector, for generating a rotation speed voltage according to a rotation speed signal corresponding to the rotation speed; a sample and hold element, coupled to the rotation speed detector, for sampling and storing the rotation speed voltage; an error amplifier, coupled to the sample and hold element, for controlling a voltage of a filter capacitor according to the rotation speed voltage and a reference voltage, to adjust an error voltage; and a pulse width modulation signal generator, coupled to the filter capacitor, for generating a pulse width modulation signal according to the error voltage and a triangle wave.

Abstract: A driving method for a motor includes sensing variation of magnetic pole of a rotator of the motor, to generate a magnetic pole sensing signal, determining dead zone of the motor according to the magnetic pole sensing signal, to generate a determination result, and adjusting voltage outputted to a coil of the rotator according to the determination result.

Abstract: A motor driving circuit for adjusting speed of the motor by changing output voltage is disclosed. One end of the motor is coupled to a variable voltage source. The motor driving circuit includes a motor-driving unit, a control unit and a determining unit. The motor-driving unit includes a first end coupled to another end of the motor, a second end coupled to a ground and a third end, and is utilized for driving the motor. The control unit is utilized for controlling the voltage between the first end and the third end of the motor-driving unit. The determining unit is coupled between the variable voltage source and the control unit, and is utilized for controlling the control unit to adjust the voltage between the first end and the third end of the motor-driving unit according to magnitude of the voltage of the variable voltage source.

Abstract: An inrush voltage clamping circuit for an electronic device for clamping an inrush voltage induced by hot plugging is disclosed. The clamp circuit includes a buffer unit and a clamp unit. The buffer unit is coupled to an input power end for receiving an inrush current of the inrush voltage. The clamp unit is coupled to the input power end and the buffer unit for controlling the buffer unit to receive the inrush current according to an input voltage of the input power end.

Abstract: A motor driving method for driving a direct-current (DC) motor, designed for avoiding a reverse current induced by the Back Electromotive Force (BEMF), includes providing a driver circuit for driving the DC motor; comparing a signal level of a terminal of the DC motor and a predetermined voltage value to produce a comparing result; and controlling a specific lower gate switch to avoid the occurrence of a reverse current of the DC motor according to the comparing result.

Abstract: A driving method for a motor includes sensing variation of magnetic pole of a rotator of the motor, to generate a magnetic pole sensing signal, determining dead zone of the motor according to the magnetic pole sensing signal, to generate a determination result, and adjusting voltage outputted to a coil of the rotator according to the determination result.

Abstract: A control method of a current limit of a DC motor includes generating a reference voltage according to a preset current limit value of a DC motor; comparing the reference voltage with the voltage drop of a power control switch which drives the DC motor to generate a compare result; and controlling the power delivered to the DC motor according to the compare result in order to limit the current of the DC motor.

Abstract: A pulse width modulation circuit capable of linearly adjusting duty cycle with voltage, which comprises an input voltage source for generating an input voltage, a regulator for generating a regulated voltage, a first voltage-dividing unit for providing a first divided voltage, a second voltage-dividing unit for providing a second divided voltage, a third voltage-dividing unit for providing a third divided voltage, a voltage adder for adding the first divided voltage and the third divided voltage for generating a high level voltage, a waveform generator for generating an oscillating signal according to the high level voltage and the third divided voltage, and a comparator having a first input terminal coupled to the second voltage-dividing unit, a second terminal coupled to the waveform generator, and an output terminal for comparing the second divided voltage with the oscillating signal to output a pulse width modulation signal through the output terminal.

Abstract: A pulse width modulation circuit capable of linearly adjusting duty cycle with voltage, which comprises an input voltage source for generating an input voltage, a regulator for generating a regulated voltage, a first voltage-dividing unit for providing a first divided voltage, a second voltage-dividing unit for providing a second divided voltage, a third voltage-dividing unit for providing a third divided voltage, a voltage adder for adding the first divided voltage and the third divided voltage for generating a high level voltage, a waveform generator for generating an oscillating signal according to the high level voltage and the third divided voltage, and a comparator having a first input terminal coupled to the second voltage-dividing unit, a second terminal coupled to the waveform generator, and an output terminal for comparing the second divided voltage with the oscillating signal to output a pulse width modulation signal through the output terminal.

Abstract: A sensorless method for starting a three-phase brushless direct-current motor includes generating a start-up control signal, a start mode selection signal, and a control signal commutation period; switching to a start mode according to the start mode selection signal; implementing a position aligning procedure according to the start-up control signal and the control signal commutation period; detecting a zero crossing point of back electromotive forces during each control signal commutation period; outputting a sensorless mode selection signal while detecting the zero crossing points of the back electromotive forces during consecutive control signal commutation periods; switching to a sensorless mode according to the sensorless mode selection signal; and detecting a zero crossing point of back electromotive forces in the sensorless mode to determine a starting result of the three-phase brushless direct-current motor.

Abstract: A motor driving circuit for adjusting speed of the motor by changing output voltage is disclosed. One end of the motor is coupled to a variable voltage source. The motor driving circuit includes a motor-driving unit, a control unit and a determining unit. The motor-driving unit includes a first end coupled to another end of the motor, a second end coupled to a ground and a third end, and is utilized for driving the motor. The control unit is utilized for controlling the voltage between the first end and the third end of the motor-driving unit. The determining unit is coupled between the variable voltage source and the control unit, and is utilized for controlling the control unit to adjust the voltage between the first end and the third end of the motor-driving unit according to magnitude of the voltage of the variable voltage source.