Abstract: An electrical device includes a coil assembly and a case structure. The coil assembly includes plural coil units in a stack arrangement. Each of the coil units includes alternate loops and vacant portions. The loops of each coil unit are aligned with the vacant portions of an adjacent coil unit. There is a spacing interval between every two adjacent loops of every two adjacent coil units. The case structure has a receptacle for accommodating the coil assembly.

Abstract: A power supply has a single stage converter for performing power factor correction to reduce high-frequency harmonics in the input current and performs resonant conversion to achieve zero-voltage switching or zero-current switching for power conversion. The inventive single stage converter includes a switching circuit, a resonant circuit, a power control circuit, and a square wave generator. The switching circuit includes at least one switch and the resonant circuit includes a LLC resonant tank. The power control circuit includes a proportional differential circuit such as a power amplifier configured in a negative feedback topology, and the square wave generator is configured to generate driving signals based on the frequency modulation control signal generated by the comparison of the sensed input current and a user-defined power level input, thereby allowing the square wave generator to regulate the switching operation of the switching circuit.

Abstract: An AC-DC converter is disclosed. The AC-DC converter includes an OFF-time clamping circuit. The OFF time clamping circuit outputs a triggering signal when a main switch circuit of the AC-DC converter is switched from ON state to OFF state. When an input AC voltage is too small, and a terminal voltage at a first current-conducting terminal of the main switch circuit of the AC-DC converter is lower than a specific voltage such that a switching control circuit can not turn on the main switch circuit again, the switching control circuit can still turn on the main switch circuit again by the triggering signal. Therefore, the OFF time of the main switch circuit is clamped. The switching control circuit can control the switching operation of the main switch circuit.

Abstract: The invention discloses a control circuit for an AC-DC converter. The control circuit includes a power control circuit for comparing an input current sensing signal generated by sensing an input current of the AC-DC converter and a power level control input and in response thereto generating a frequency modulation control signal, in which the frequency modulation control signal is used to control the output power of the AC-DC converter and suppress harmonics of the input current, and a square wave generator connected to the power control circuit for generating a driving signal used to drive the switch circuit of the AC-DC converter according to the frequency modulation control signal, in which the frequency of the driving signal is varied with the frequency modulation control signal, thereby suppressing harmonics of the input current and regulating the switching frequency the AC-DC converter, and regulating the output power of the AC-DC converter.

Abstract: The invention discloses a power supply having a single stage converter for performing power factor correction to reduce high-frequency harmonics in the input current and performing resonant conversion to achieve zero-voltage switching or zero-current switching for power conversion. The inventive single stage converter includes a switching circuit, a resonant circuit, a power control circuit, and a square wave generator. The switching circuit includes at least one switch and the resonant circuit includes a LLC resonant tank. The power control circuit includes a proportional differential circuit such as a power amplifier configured in a negative feedback topology, and the square wave generator is configured to generate driving signals based on the frequency modulation control signal generated by the comparison of the sensed input current and a user-defined power level input, thereby allowing the square wave generator to regulate the switching operation of the switching circuit.

Abstract: An AC-DC converter is disclosed. The AC-DC converter includes an OFF-time clamping circuit. The OFF time clamping circuit outputs a triggering signal when a main switch circuit of the AC-DC converter is switched from ON state to OFF state. When an input AC voltage is too small, and a terminal voltage at a first current-conducting terminal of the main switch circuit of the AC-DC converter is lower than a specific voltage such that a switching control circuit can not turn on the main switch circuit again, the switching control circuit can still turn on the main switch circuit again by the triggering signal. Therefore, the OFF time of the main switch circuit is clamped. The switching control circuit can control the switching operation of the main switch circuit.

Abstract: An electrical device includes a coil assembly and a case structure. The coil assembly includes plural coil units in a stack arrangement. Each of the coil units includes alternate loops and vacant portions. The loops of each coil unit are aligned with the vacant portions of an adjacent coil unit. There is a spacing interval between every two adjacent loops of every two adjacent coil units. The case structure has a receptacle for accommodating the coil assembly.

Abstract: The invention discloses a control circuit for an AC-DC converter. The control circuit includes a power control circuit for comparing an input current sensing signal generated by sensing an input current of the AC-DC converter and a power level control input and in response thereto generating a frequency modulation control signal, in which the frequency modulation control signal is used to control the output power of the AC-DC converter and suppress harmonics of the input current, and a square wave generator connected to the power control circuit for generating a driving signal used to drive the switch circuit of the AC-DC converter according to the frequency modulation control signal, in which the frequency of the driving signal is varied with the frequency modulation control signal, thereby suppressing harmonics of the input current and regulating the switching frequency the AC-DC converter, and regulating the output power of the AC-DC converter.