Abstract: A drive circuit for an electric motor having a wound stator and a permanent magnet rotor, includes a controllable bidirectional AC switch connected in series with a stator winding between two terminals for connecting to an AC power supply. First and second position sensors detect the position of magnetic poles of the rotor. A voltage regulating circuit is connected between the two terminals and the controllable bidirectional AC switch and configured to supply power to the first sensor during the positive cycle and to the second position sensor during the negative cycle of the AC power supply such that the controllable bidirectional AC switch is switched between a conductive state and a non-conductive state in a preset manner, thus enabling the stator to rotate the rotor in only one predetermined direction during start-up.

Abstract: A drive circuit for an electric motor connected in series with an AC power source between a first node and a second node. The drive circuit includes a controllable bidirectional AC switch, an AC-DC conversion circuit connected in parallel with the controllable bidirectional AC switch between the first node and the second node, a position sensor configured to detect a position of a rotor of the motor, and a switch control circuit configured to control the controllable bidirectional AC switch to be conductive or non-conductive in a predetermined way, based on the position of the rotor and a polarity of the AC power source.

Abstract: A control circuit includes: an input terminal for receiving an input AC voltage; a voltage decreasing unit for decreasing the input AC voltage; an A-D converter for converting the decreasing AC voltage to a DC voltage; a driving unit for receiving the DC voltage and to driving a motor, a detecting unit for detecting the DC voltage; and a current shunt unit configured to be conductive to lower the DC voltage at the output terminal of the A-D converter to a voltage which is less than a threshold voltage when the detecting signal indicates that the detected DC voltage exceeds the threshold value. A motor device includes the control circuit and a motor.

Abstract: A drive circuit for an electric motor, has a driving source unit, configured to generate a driving source signal and a driving unit, connected to the motor and configured to drive the motor according to the driving source signal. A sensing unit senses the actual speed of the motor. A control unit stops operation of the motor when the actual speed of the motor falls below a predetermined level. A timing unit counts a predetermined time period from the time the motor stops operation. The motor resumes operation at the end of the predetermined time period.

Abstract: A control circuit has an input terminal for receiving an input voltage, an energy accumulator for storing electric energy from the input terminal and supplying power to an electrical load, and an over-voltage protection unit for lowering the voltage at the input terminal when the voltage at an output terminal of the energy accumulator exceeds a predetermined threshold value. A motor device combines the control circuit with an electric motor as the load.

Abstract: A power converting circuit for supplying power to an inductive load, includes an inductance, a switching circuit and an energy saving circuit. The inductance is charged when the switching circuit is conductive and discharges energy to the energy saving circuit and the inductive load when the switching circuit is nonconductive. The energy saving circuit discharges energy to the inductive load when the switching circuit is conductive.

Abstract: A power conversion circuit for supplying power to an inductive load, includes a switching circuit and an energy saving circuit. The inductive load is supplied with electrical power and the energy saving circuit is charged when the switching circuit is conductive, and the inductive load is disconnected from the electrical power supply and the energy stored in the energy saving circuit is discharged to the inductive load when the switching circuit is nonconductive.

Abstract: A control circuit for a DC motor, has: a first and second input ports for connection to a DC source; a H-bridge driving circuit, having first and second switches connected in series between the input ports, and third and fourth switches connected in series between the input ports, a first output port between the first and second switches and a second output port between the third and fourth switches, and a shunt circuit and/or a blocking circuit. The motor is connected between the first and second output ports. The shunt circuit is connected between the first second output ports and has a resistance that will decrease in response to BEMF generated by the motor. The blocking circuit is connected in series with the motor between the output ports and has a resistance that increases in response to BEMF generated by the motor.

Abstract: A power supply circuit has an input terminal for electrically connecting to an active wire of an AC power supply, an earth terminal for electrically connecting to a neutral or ground wire of the AC power supply, and a voltage decreasing unit. The voltage decreasing unit has an adjustable capacitor unit with adjustable capacitance for decreasing an AC voltage applied to the input terminal and an output terminal for outputting the decreased AC voltage. An electric motor is combined with the power supply circuit to form a motor device.

Abstract: A power supply circuit includes two half bridge circuits, a controller and two terminals for connecting a motor. The controller includes a signal input terminal, a phase inverter, a wiring board having four soldering pads, and two conductors. The four soldering pads are connected to the signal terminal, an output terminal of the phase inverter, control terminals of lower switches of the two half bridge circuits. Two ends of the first conductor are connected to the first and the fourth soldering pads and two ends of the second conductor are connected to the second and the third soldering pads. Alternatively, two ends of the first conductor are connected to the first and the third soldering pads and two ends of the second conductor are connected to the second and the fourth soldering pads.

Abstract: A power supply circuit includes two half bridge circuits, a controller and two terminals for connecting a motor. The controller includes a signal input terminal, a phase inverter, a wiring board having four soldering pads, and two conductors. The four soldering pads are connected to the signal terminal, an output terminal of the phase inverter, control terminals of lower switches of the two half bridge circuits. Two ends of the first conductor are connected to the first and the fourth soldering pads and two ends of the second conductor are connected to the second and the third soldering pads. Alternatively, two ends of the first conductor are connected to the first and the third soldering pads and two ends of the second conductor are connected to the second and the fourth soldering pads.

Abstract: A power supply circuit has an input terminal for electrically connecting to an active wire of an AC power supply, an earth terminal for electrically connecting to a neutral or ground wire of the AC power supply, and a voltage decreasing unit. The voltage decreasing unit has an adjustable capacitor unit with adjustable capacitance for decreasing an AC voltage applied to the input terminal and an output terminal for outputting the decreased AC voltage. An electric motor is combined with the power supply circuit to form a motor device.

Abstract: A control circuit has an input terminal for receiving an input voltage, an energy accumulator for storing electric energy from the input terminal and supplying power to an electrical load, and an over-voltage protection unit for lowering the voltage at the input terminal when the voltage at an output terminal of the energy accumulator exceeds a predetermined threshold value. A motor device combines the control circuit with an electric motor as the load.