Abstract: A circuit and method for realizing a combined connection of neutral wires or live wires using phase information of the neutral wires and the live wires are provided. The circuit includes a phase detection module. The phase detection module is connected to a power grid via the live wire VL and the neutral wire VN. The phase detection module includes a high-voltage phase detector, a first inverter and a second inverter. The output of the high-voltage phase detector is sequentially connected to the first inverter and the second inverter. The method includes: arranging nodes on the live wire VL and the neutral wire VN of the power grid, respectively; defining the nodes by determining a phase relationship that a high-voltage signal first appears on the live wire VL or the neutral wire VN; and connecting systems to be connected in parallel to the power grid through the nodes.

Abstract: A circuit and method for realizing a combined connection of neutral wires or live wires using phase information of the neutral wires and the live wires are provided. The circuit includes a phase detection module. The phase detection module is connected to a power grid via the live wire VL and the neutral wire VN. The phase detection module includes a high-voltage phase detector, a first inverter and a second inverter. The output of the high-voltage phase detector is sequentially connected to the first inverter and the second inverter. The method includes: arranging nodes on the live wire VL and the neutral wire VN of the power grid, respectively; defining the nodes by determining a phase relationship that a high-voltage signal first appears on the live wire VL or the neutral wire VN; and connecting systems to be connected in parallel to the power grid through the nodes.

Abstract: A switch mode power supply (SMPS) system includes a rectifying circuit for coupling to an AC input voltage and a transformer having a primary winding for coupling to the rectifying circuit and a secondary winding coupled to the primary winding. The system also has a power switch coupled to the primary winding and a control circuit coupled to the power switch. The control circuit is configured to control current flow in the primary winding such that an envelope waveform formed by peak points of current pulses is in phase with the magnitude of the AC input voltage. Moreover, the SMPS system is configured to provide a constant average output current.

Abstract: A driver circuit for an LED (light-emitting diode) lamp includes a transformer having a primary winding and a secondary winding, a dimmer circuit coupled to a power source for varying an input voltage to the primary winding, and an output rectifying circuit coupled to the secondary winding for providing an output current to the LED lamp. The driver circuit also includes a controller coupled to the dimmer circuit to receive an average input voltage signal (DIM) from the dimmer circuit. The controller is configured to vary the output current according to the average input voltage.

Abstract: A bleeder circuit is provided in a switched mode power supply (SMPS) that provides a compensation current when the loop current drops below the holding current of the TRIAC to alleviate light flickering problem. Further, automatic power factor correction is also provided in embodiments of the invention, which enables the output current to be in phase with the input voltage. The power factor correction not only improves the efficiency of the power supply, it can also reduce the compensation current and the duration in which compensation current flows, thereby reducing the power loss in the bleeder circuit.

Abstract: A bleeder circuit is provided in a switched mode power supply (SMPS) that provides a compensation current when the loop current drops below the holding current of the TRIAC to alleviate light flickering problem. Further, automatic power factor correction is also provided in embodiments of the invention, which enables the output current to be in phase with the input voltage. The power factor correction not only improves the efficiency of the power supply, it can also reduce the compensation current and the duration in which compensation current flows, thereby reducing the power loss in the bleeder circuit.

Abstract: A switch mode power supply (SMPS) system includes a rectifying circuit for coupling to an AC input voltage and a transformer having a primary winding for coupling to the rectifying circuit and a secondary winding coupled to the primary winding. The system also has a power switch coupled to the primary winding and a control circuit coupled to the power switch. The control circuit is configured to control current flow in the primary winding such that an envelope waveform formed by peak points of current pulses is in phase with the magnitude of the AC input voltage. Moreover, the SMPS system is configured to provide a constant average output current.

Abstract: A switch mode power supply (SMPS) system includes a rectifying circuit for coupling to an AC input voltage and a transformer having a primary winding for coupling to the rectifying circuit and a secondary winding coupled to the primary winding. The system also has a power switch coupled to the primary winding and a control circuit coupled to the power switch. The control circuit is configured to control current flow in the primary winding such that an envelop waveform formed by peak points of current pulses are in phase with the magnitude of the AC input voltage. Moreover, the SMPS system is configured to provide a constant average output current.

Abstract: A controller for a switched mode power supply (SMPS) is provided. The SMPS is equipped with a transformer having a primary side winding, a secondary winding, and an auxiliary winding. The controller includes a detection circuit for detecting a transition from a first output load condition to a second output load condition of the SMPS and a control circuit coupled to the detection circuit and being configured to output one or more control signals in response to the detected output load transition. Depending on the embodiment, the one or more control signals include a first control signal for turning on a power switch to cause a current flow in a primary winding of the SMPS and/or one or more second control signals for turning off one or more functional circuit blocks in the controller.

Abstract: A driver circuit for an LED (light-emitting diode) lamp includes a transformer having a primary winding and a secondary winding, a dimmer circuit coupled to a power source for varying an input voltage to the primary winding, and an output rectifying circuit coupled to the secondary winding for providing an output current to the LED lamp. The driver circuit also includes a controller coupled to the dimmer circuit to receive an average input voltage signal (DIM) from the dimmer circuit. The controller is configured to vary the output current according to the average input voltage.

Abstract: A switch-mode power supply (SMPS) includes a transformer having a primary winding coupled to a power switch, a secondary winding for providing an output of the power supply, and a controller. The controller includes a first input terminal for receiving a current sensing signal related to a current in the primary winding, a second input terminal for receiving a feedback signal related to a current in the secondary winding, and an output terminal for providing a control signal to turn on and off the power switch. When the feedback signal is higher than a first reference voltage, the controller is configured to cause the SMPS to maintain a constant output current at a first current magnitude. When the feedback signal is lower than the first reference voltage, the controller is configured to cause the SMPS to provide a second output current at a second current magnitude higher than the first current magnitude.

Abstract: A system for driving an LED (light-emitting diode) lamp includes a dimmer circuit coupled to a line input voltage for varying a magnitude of an input voltage and a transformer having a primary winding, a secondary winding, and one or more auxiliary windings, the primary winding coupled to the dimmer circuit. The system also includes an output rectifying circuit coupled to the secondary winding for providing an output current to the LED lamp and a power switch coupled to the primary winding for controlling a current flow in the primary winding. The system further includes a controller having a comparator and a capacitor for providing a control signal to control the power switch for regulating the output current.

Abstract: A switch-mode power supply (SMPS) includes a transformer having a primary winding coupled to a power switch, a secondary winding for providing an output of the power supply, and a controller. The controller includes a first input terminal for receiving a current sensing signal related to a current in the primary winding, a second input terminal for receiving a feedback signal related to a current in the secondary winding, and an output terminal for providing a control signal to turn on and off the power switch. When the feedback signal is higher than a first reference voltage, the controller is configured to cause the SMPS to maintain a constant output current at a first current magnitude. When the feedback signal is lower than the first reference voltage, the controller is configured to cause the SMPS to provide a second output current at a second current magnitude higher than the first current magnitude.

Abstract: A system for driving an LED (light-emitting diode) lamp includes a dimmer circuit coupled to a line input voltage for varying a magnitude of an input voltage and a transformer having a primary winding, a secondary winding, and one or more auxiliary windings, the primary winding coupled to the dimmer circuit. The system also includes an output rectifying circuit coupled to the secondary winding for providing an output current to the LED lamp and a power switch coupled to the primary winding for controlling a current flow in the primary winding. The system further includes a controller having a comparator and a capacitor for providing a control signal to control the power switch for regulating the output current.

Abstract: A switch mode power supply (SMPS) system includes a rectifying circuit for coupling to an AC input voltage and a transformer having a primary winding for coupling to the rectifying circuit and a secondary winding coupled to the primary winding. The system also has a power switch coupled to the primary winding and a control circuit coupled to the power switch. The control circuit is configured to control current flow in the primary winding such that an envelop waveform formed by peak points of current pulses are in phase with the magnitude of the AC input voltage. Moreover, the SMPS system is configured to provide a constant average output current.

Abstract: A controller for a switched mode power supply (SMPS) is provided. The SMPS is equipped with a transformer having a primary side winding, a secondary winding, and an auxiliary winding. The controller includes a detection circuit for detecting a transition from a first output load condition to a second output load condition of the SMPS and a control circuit coupled to the detection circuit and being configured to output one or more control signals in response to the detected output load transition. Depending on the embodiment, the one or more control signals include a first control signal for turning on a power switch to cause a current flow in a primary winding of the SMPS and/or one or more second control signals for turning off one or more functional circuit blocks in the controller.