Abstract: A noise filter circuit uses open loop signal processing to process the signal that causes the noise and generate a signal to be fed back into the system to cancel noise currents.

Abstract: A control circuit is disclosed for lighting applications having a load and an AC leading-edge phase-cut dimmer comprising a phase-cutting switch, the circuit comprising: a detection circuit for detecting a deadlock state of the dimmer; and an activation circuit configured to, in response to the detection circuit detecting a deadlock state of the dimmer, supply a DC current to the dimmer to exit the deadlock state by activating the dimmer. A method of operating such a control circuit is also disclosed.

Abstract: A circuit is disclosed for driving a plurality of LED strings from an AC supply and arranged to, in use, drive current through a series arrangement of a plurality N of the LED strings when the AC voltage is sufficient to drive the plurality N of the LED strings: the circuit comprising a first current source configured to be switchably connected to a one end of said series arrangement of N LED strings; a series combination of a second current source and a heat dissipater, wherein the series combination of the second current source and the heat dissipater is arranged in parallel with the first current source; and a current balancer for balancing the current through the first current source and the second current source. A driver for such a circuit is also disclosed.

Abstract: An electronic switching device comprises a first bipolar junction transistor (BJT) (2a) adapted to control the flow of current between a pair of switching terminals; a charge recovery circuit coupled to the base of the first BJT (2a) and adapted to establish a supply voltage across a capacitor (5) by storing in the capacitor (5) charge carriers accumulated in the base of the first BJT (2a) during application of a base drive current, the quantity of accumulated charge carriers depending on the base drive current; and a controllable current source (4) adapted to control the base drive current, thereby controlling the supply voltage.

Abstract: A noise filter circuit uses open loop signal processing to process the signal that causes the noise and generate a signal to be fed back into the system to cancel noise currents.

Abstract: A control circuit is disclosed for lighting applications having a load and an AC leading-edge phase-cut dimmer comprising a phase-cutting switch, the circuit comprising: a detection circuit for detecting a deadlock state of the dimmer; and an activation circuit configured to, in response to the detection circuit detecting a deadlock state of the dimmer, supply a DC current to the dimmer to exit the deadlock state by activating the dimmer. A method of operating such a control circuit is also disclosed.

Abstract: An electronic switching device comprises a first bipolar junction transistor (BJT) (2a) adapted to control the flow of current between a pair of switching terminals; a charge recovery circuit coupled to the base of the first BJT (2a) and adapted to establish a supply voltage across a capacitor (5) by storing in the capacitor (5) charge carriers accumulated in the base of the first BJT (2a) during application of a base drive current, the quantity of accumulated charge carriers depending on the base drive current; and a controllable current source (4) adapted to control the base drive current, thereby controlling the supply voltage.

Abstract: A power supply system (1) comprises a power brick (3) which comprises a power converter (30) arranged in a first housing (2). The power converter (30) converts an AC-mains input voltage (VM) into an AC-output voltage (VO) which has a higher frequency than the AC-mains input voltage (VM). A power supply circuit (7) supplies a DC-voltage (PVi) to an application (8). The power supply circuit (7) and the application (8) both being arranged in a second housing (6) mechanically separated from the first housing (2). A cable (5) interconnects the power brick (3) and the power supply circuit (7) to supply the AC-output voltage (VO) to the power supply circuit (7). The power supply circuit (7) comprises a rectifier circuit (RE1, RE2, RE3) which rectifies the AC-output voltage (VO) to supply the DC-voltage (PVi) to the application (8).

Abstract: A switched mode power supply includes an input for receiving an input signal voltage, a flyback converter circuit arrangement and an output for delivering a regulated output signal voltage. The switched mode power supply further includes a boost converter arranged to be operatively combined with the flyback converter, and functioning such that the combined converter operates in a boost mode when the input voltage is above a threshold value, and in a flyback mode when the input voltage is below the threshold value.

Abstract: An LLC power converter has an output voltage which is determined by a frequency controller controlling the frequency of an on and off switching of the switches (5, 6) of the converter. In order to stabilize the output voltage at varying output currents, a control circuit feeds back the variation of the total current (I) in the converter to the frequency controller (22, 25) for correcting the frequency of the on and off switching of the switches.

Abstract: The present invention provides for a switched mode power supply having an input for receiving an input signal voltage, a flyback converter circuit arrangement and an output for delivering a regulated output signal voltage, and including a boost converter arranged to be operatively combined with the said flyback converter, and functioning such that the combined converter operates in a boost mode when the input voltage is above a threshold value, and in a flyback mode when the input voltage is below the threshold value.

Abstract: A half-bridge circuit which is operated as a double down-converter is equipped with a second inductor and power feedback capacitors and diodes. The power factor of the circuit is substantially improved thereby.