Abstract: A fan system comprising a motor, a motor driving circuit and a control unit is disclosed. The motor driving circuit is coupled to the motor. The control unit is coupled to the motor driving circuit, generates a forward rotation command for controlling the motor to rotate in a predetermined direction when the control unit receives electrical power, and generates a backward rotation command for controlling the motor to rotate in a direction opposite to the predetermined direction when the control unit fails to receive the electrical power.

Abstract: An alternating current (AC) light-emitting diode (LED) lamp includes a first AC power end, a second AC power end, a lighting module and a direct current (DC) power output circuit. The lighting module has a first end, a second end and at least one LED unit, wherein the first end is electrically coupled to the first AC power end. The at least one LED unit has one or more LEDs connected in series. The DC power output circuit has a first end and a second end, wherein the second end of the DC power output circuit is electrically coupled to the second AC power end, while the first end of the DC power output circuit is electrically coupled to the second end of the lighting module. The DC power output circuit has a DC output side.

Abstract: A lamp circuit is disclosed, comprising a direct current (DC) power supplier adapted to provide a supply voltage, a driving unit coupled to the DC power supplier so as to receive the supply voltage, and a light-radiating module coupled to the driving unit and having a DC output side. The driving unit generates a constant DC current that passes through the light-radiating module such that a DC voltage to be supplied to a DC load is built at the DC output side.

Abstract: The present invention relates to a fan control system. The fan control system includes a first micro controller, a second micro controller and a first logic circuit. The first micro controller provides at least one first control signal. The second micro controller is connected to the first micro controller. The second micro controller detects operational status of the first micro controller, and provides at least one second control signal. The first logic circuit receives the first control signal and the second control signal to process logic operation and to generate at least one driving signal to fan. The fan control system of the invention utilizes two micro controllers, when one of the two micro controllers malfunctions, the first logic circuit allows the other micro controller to continue proper operation of the fan, thereby preventing the problem of insufficient heat dissipation that results from malfunction of the single micro controller of a conventional fan control system.

Abstract: A fan device with improved speed control module includes a stator, a rotor, and a speed control module. The stator has a driving unit outputting currents for the stator to generate alternative magnetic fields and thus turn the rotor. The speed control module includes a control unit and a speed adjusting circuit, with the control unit generating a control command for the driving unit and further outputting a state signal for the speed adjusting circuit to control whether a PWM signal enters the control circuit or not.

Abstract: A brushless DC motor drive circuit includes a drive unit and a transient current suppression circuit. The drive unit comprises a Hall component, a drive component, a first transistor and a second transistor. The Hall component detects the position of a rotor of the DC motor and transmits digital command signals to the drive component; the drive component further generates two complementary digital command signals; and the first and second transistors connect with the drive component respectively. The transient current suppression circuit comprises a first auxiliary transistor and a second auxiliary transistor, wherein the first auxiliary transistor receives one of the complementary digital command signals different from the other one received by the first transistor and the second auxiliary transistor receives the other one of the complementary digital command signals different from the one received by the second transistor.

Abstract: A PWM motor drive circuit includes a drive IC member, a PWM converter circuit and a potential limiter. The drive IC member electrically connects with a motor coil and further includes a pin electrically connected with the PWM converter circuit. The potential limiter has a first terminal electrically connected with a point between the pin of the drive IC member and the PWM converter circuit, and a second terminal electrically connected with a power source to supply an initial voltage to the pin of the drive IC member via the potential limiter. When the motor starts, the potential limiter can adjust of the initial voltage supplying to the pin of the drive IC member so that the drive IC member cannot unexpectedly enter a stop or high-speed mode.

Abstract: A PWM motor drive circuit includes a drive IC member, a PWM converter circuit and a potential limiter. The drive IC member electrically connects with a motor coil and further includes a pin electrically connected with the PWM converter circuit. The potential limiter has a first terminal electrically connected with a point between the pin of the drive IC member and the PWM converter circuit, and a second terminal electrically connected with a power source to supply an initial voltage to the pin of the drive IC member via the potential limiter. When the motor starts, the potential limiter can adjust of the initial voltage supplying to the pin of the drive IC member so that the drive IC member cannot unexpectedly enter a stop or high-speed mode.

Abstract: A frequency-variable PWM motor drive circuit includes a drive IC member, a Hall IC member, a PWM converter circuit and a compensation unit. The drive IC member electrically connects with the Hall IC member, the drive IC member further includes a pin electrically connected with the compensation unit and the PWM converter circuit. The PWM converter circuit has a PWM input pin to receive a PWM signal, and converts it into a voltage signal. The compensation unit connects between the pin of the drive IC member and the PWM converter circuit. In operation, the compensation unit can improve a waveform of the voltage signal supplied from the PWM converter circuit, and then output it to the pin of the drive IC member. Consequently, the drive IC member can be steadily operated at predetermined motor speeds under various frequencies of the PWM signals.

Abstract: A frequency-variable PWM motor drive circuit includes a drive IC member, a Hall IC member, a PWM converter circuit and a compensation unit. The drive IC member electrically connects with the Hall IC member, the drive IC member further includes a pin electrically connected with the compensation unit and the PWM converter circuit. The PWM converter circuit has a PWM input pin to receive a PWM signal, and converts it into a voltage signal. The compensation unit connects between the pin of the drive IC member and the PWM converter circuit. In operation, the compensation unit can improve a waveform of the voltage signal supplied from the PWM converter circuit, and then output it to the pin of the drive IC member. Consequently, the drive IC member can be steadily operated at predetermined motor speeds under various frequencies of the PWM signals.

Abstract: A brushless dc motor includes a PWM drive IC member, a Hall IC member, a PWM converter circuit and a Rotational Detection (RD) signal line. The PWM drive IC member electrically connects with the Hall IC member, the PWM drive IC member further includes a pin electrically connected with the PWM converter circuit. The RD signal line connects between the pin of the PWM drive IC member and the PWM converter circuit, and further connects with a RD signal source to supply RD signals to the pin of the PWM drive IC member. When the motor is jammed, the jammed RD signals can build a predetermined voltage which can determine the PWM drive IC member to be restarted or operated at a predetermined-speed mode. In this circumstance, no inrush current of the jammed motor will occur.

Abstract: A PWM motor drive circuit includes a drive IC member, a Hall IC member, a PWM converter circuit and a capacitor. The drive IC member electrically connects with the Hall IC member, the drive IC member further includes a pin electrically connected with the PWM converter circuit. The capacitor connects in parallel between the pin of the drive IC member and the PWM converter circuit, and further connects with a power source to supply a voltage to the pin of the drive IC member. When the motor is started, the capacitor can prevent occurring zero volts at the pin of the drive IC member so that the drive IC member cannot unexpectedly enter a high-speed mode.

Abstract: A brushless dc motor includes a conversion circuit and a dc motor drive circuit. The conversion circuit includes a rectifier unit, a pulse-wave-absorbing unit, a filter unit, a voltage-stabilizing control unit and a voltage-stabilizing unit. The rectifier unit, the pulse-wave-absorbing unit and the filter unit are serially connected between an ac power source and the dc motor drive circuit. The ac power source is rectified, stabilized and filtered to thereby supply with a dc voltage to the dc motor drive circuit. The voltage-stabilizing control unit and the voltage-stabilizing unit are serially connected between the rectifier unit and the dc motor drive circuit so as to limit a passage of a high voltage and to allow a passage of a low voltage through the dc motor drive circuit. Thereby, the voltage-stabilizing control unit and the voltage-stabilizing unit are commonly in control of the operation of the dc motor drive circuit.

Abstract: A brushless dc motor includes a conversion circuit and a dc motor drive circuit. The conversion circuit includes a rectifier unit, a pulse-wave-absorbing unit, a filter unit, a voltage-stabilizing control unit and a voltage-stabilizing unit. The rectifier unit, the pulse-wave-absorbing unit and the filter unit are serially connected between an ac power source and the dc motor drive circuit. The ac power source is rectified, stabilized and filtered to thereby supply with a dc voltage to the dc motor drive circuit. The voltage-stabilizing control unit and the voltage-stabilizing unit are serially connected between the rectifier unit and the dc motor drive circuit so as to limit a passage of a high voltage and to allow a passage of a low voltage through the dc motor drive circuit. Thereby, the voltage-stabilizing control unit and the voltage-stabilizing unit are commonly in control of the operation of the dc motor drive circuit.