A converter circuit includes first and second input terminals, control circuitry, and a storage capacitor. The first and second input terminals are configured for connection to an AC power supply to receive an AC signal. The control circuitry is coupled to the first and second input terminals. A terminal of the storage capacitor is coupled to an output node of the control circuitry. The storage capacitor is charged by the control circuitry and configured for use as a DC power source. The control circuitry is configured to couple the first input terminal to the storage capacitor during a portion of a positive half-cycle of the input AC signal to charge the storage capacitor and to decouple the first input terminal from the storage capacitor during an entirety of each negative half-cycle of the input AC signal, to thereby prevent discharging of the storage capacitor by the input AC signal.

A power conversion system includes: a power converter connected between a DC power source and an AC power source; an AC switch connected between the power converter and the AC power source; an AC capacitor connected on the power converter side relative to the AC switch, on an output side of the power converter; and a control device configured to, in a state in which the AC switch is open, recognize a voltage of the AC capacitor and control the power converter to bring an output voltage of the power converter close to a voltage of the AC power source from the voltage of the AC capacitor gradually or in a step-by-step manner, and then close the AC switch. The power conversion system can suppress overcurrent at a time of start-up of a power converter and inrush current at a time of interconnection to an AC power source.

A method and apparatus for modulating a load by means of control command obtained by varying conduction angle of AC voltage is provided. Under normal operation, conduction angle of AC is approximate to 180 degrees. When a state change command of the load is to be executed, the angle of conduction angle is changed by a conduction angle modulation circuit of control end. After a conduction angle detection circuit of the load end detects the conduction angle, a control unit decodes the information of the conduction angle, and controls the load to perform a corresponding operation. The method and apparatus do not need to add an extra control wiring for the load, and may use the conduction angle of an AC power supply to effectively perform multifunctional modulations on the load with existing power lines, and the defect of a low power commonly found in a traditional dimmer is overcome.

An illumination device and method are provided for controlling light emitting diodes (LEDs). The LEDs (specifically, the LED loads) are controlled, e.g., brightness and color of the LED loads, independent of a phase-cut dimmer applied to the AC mains feeding a DC power supply. The power supply is active dependent upon the duration of a conduction angle supplied from the dimmer. The power supply, however, produces drive currents that are independent from the conduction angle by using a two-stage power supply and a relatively slow and fast control loops that are controlled through a microprocessor based control circuit. Parameters stored in the control circuit are drawn by the microprocessor to control the two-stage power supply to produce the drive currents independent and decoupled from the conduction angle yet dependent on the controller parameters.

A load control device for controlling power delivered from an alternating-current power source to an electrical load may comprise a controllably conductive device, a control circuit, and an overcurrent protection circuit that is configured to be disabled when the controllably conductive device is non-conductive. The control circuit may be configured to control the controllably conductive device to be non-conductive at the beginning of each half-cycle of the AC power source and to render the controllably conductive device conductive at a firing time during each half-cycle (e.g., using a forward phase-control dimming technique). The overcurrent protection circuit may be configured to render the controllably conductive device non-conductive in the event of an overcurrent condition in the controllably conductive device. The overcurrent protection circuit may be disabled when the controllably conductive device is non-conductive and enabled after the firing time when the controllably conductive device is rendered conductive during each half-cycle.

A small cell networking device mountable to a streetlight fixture includes circuitry for converting alternating current power into direct current (DC) power and providing a digitally stable ground for operation of the small cell device. The circuitry includes a transformer isolating a primary side from a secondary side of the circuitry. A switching controller on the primary side directs a switching circuit to selectively permit current flow through a primary side of the transformer to a first ground node on the primary side. A secondary winding of the transformer sources a rectified DC output relative to a second ground node that is isolated from the first ground node. In some cases, compensation on the secondary winding side provides isolated feedback to the controller, such as via an optical isolator. The controller directs the switching circuit based at least on the feedback and input from an auxiliary winding of the transformer.

A high voltage generator is provided. The high voltage generator includes an inverter circuit coupled to receive a direct-current (DC) input voltage, a resonant circuit coupled to the inverter circuit, a transformer coupled to the resonant circuit and also coupled to provide a high voltage output to a high voltage device, and a phase control circuit coupled to receive a voltage across and a current through the resonant circuit and also coupled to the inverter circuit. The phase control circuit generates control signals to drive the inverter circuit. The control signals drive the inverter circuit to keep the resonant circuit operating in an inductive region.

A voltage-regulating phase-cut dimmable power supply includes an electromagnetic interference filter circuit, a rectifier circuit, a power conversion circuit, a transformer, a rectifier and filter circuit, a phase-cut dimming signal conversion circuit, a first optocoupler, a dimming signal conversion circuit, a voltage comparison control circuit, a second optocoupler, a pulse width modulation (PWM) control circuit, and a voltage sampling circuit. The electromagnetic interference filter circuit, the rectifier circuit, the power conversion circuit, the transformer and the rectifier and filter circuit are electrically connected in sequence. The phase-cut dimming signal conversion circuit, the first optocoupler, the dimming signal conversion circuit, the voltage comparison control circuit, the second optocoupler and the PWM control circuit are electrically connected in sequence to an output end of the electromagnetic interference filter circuit. The voltage sampling circuit is electrically connected to the voltage comparison control circuit and an output end of the rectifier and filter circuit.

This application relates to methods and apparatus for powering microcontrollers (104), in particular for powering microcontrollers of a personal care product, such as a shaver product (107). The microcontroller is arranged such that a first output port (206-1) of a plurality of output ports of the microcontroller receives, in use, an AC waveform. Each output port has an associated high-side switch (207) electrically connected between the output port and a high-side DC voltage rail and an associated low-side switch (208) electrically connected between the output port and a low-side DC voltage rail. A processing module (202) of the microcontroller is configured to monitor a phase of the AC waveform and to control switching of the associated high-side and low-side switches of the first output port based on the phase of the AC waveform so as to provide a rectified voltage between the high-side DC voltage rail and the low-side voltage rail for powering the processing module. The processing module (202) also controls switching of the associated switches of at least a further output port to output a control signal for controlling at least one aspect of operation of a host device. The processing module is further configured to maintain the associated high-side switch of the first output port in a turned-off state when a monitored voltage of the AC waveform at the first output port is between zero and a monitored voltage at the high-side DC voltage rail, and to maintain the associated high-side switch of the first output port in a turned-on state when the monitored voltage of the AC waveform at the first output port is greater than the monitored voltage at the high-side DC voltage rail.

In an insulated resonance circuit device, a first resonance circuit includes first and second LC resonance circuits electromagnetically coupled to each other and electrically insulated from each other, oscillates at a predetermined first resonance frequency based on an input AC voltage, and outputs an oscillation signal voltage. The second resonance circuit having a second resonance frequency substantially identical to the first resonance frequency resonates with the oscillation signal voltage to detect the oscillation signal voltage, and outputs the detected oscillation signal voltage. A control circuit compare the oscillation signal voltage from the second resonance circuit with a comparison signal voltage for obtaining a predetermined target output voltage and/or a predetermined target output current to generate and output gate signals for controlling a rectifier circuit.