Abstract: A driver circuit comprising an input inductor for receiving an input current provided to the driver circuit, and one or more switchable capacitors. Each switchable capacitor is switchable to connect in parallel across the input inductor and to disconnect from the input inductor, the input inductor and the switchable capacitors together thereby providing a variable impedance corresponding to the number of switchable capacitors are switched to connect to the input inductor, with the variable impedance variably limiting the input current. An associated method and an associated system are also provided.

Abstract: A three-phase LED driver can include: an input voltage having a first phase voltage, a second phase voltage, and a third phase voltage; an input inductor connected to the input voltage; an input capacitor connected between the input voltage and the input inductor; a rectifier connected to the input inductor and having a first terminal and a second terminal; a first capacitor connected between the first terminal and the second terminal of the rectifier; and a filter connected to the first terminal of the rectifier.

Abstract: The present invention provides an apparatus for wireless power transfer including three or more coils, each coil defining a respective coil plane, and the coils being arranged in one or more power flow paths whereby each coil can be magnetically coupled to one or more of the other coils thereby to wirelessly transfer power along the one or more power flow paths. The present invention also provides a method for wirelessly transferring power, the method including: providing three or more coils, each coil defining a respective coil plane; and arranging the coils in one or more power flow paths whereby each coil can be magnetically coupled to one or more of the other coils thereby to wirelessly transfer power along the one or more power flow paths.

Abstract: This invention is concerned with the control and design of a LED lighting system that does not need electrolytic capacitors in the entire system and can generate light output with reduced luminous flux fluctuation. The proposal is particularly suitable, but not restricted to, off-line applications in which the lighting system is powered by the ac mains. By eliminating electrolytic capacitors which have a limited lifetime of typically 15000 hours, the proposed system can be developed with passive and robust electrical components such as inductor and diode circuits, and it features long lifetime, low maintenance cost, robustness against extreme temperature variations and good power factor. No extra electronic control board is needed for the proposed passive circuits, which can become dimmable systems if the ac input voltage can be adjusted by external means.

Abstract: Provided is a current mirror circuit (1) for balancing respective currents in a plurality of parallel circuit branches (2) in a target circuit (3), the current mirror circuit (1) including: a plurality of balancing transistors (4), each having a connector (5), an emitter (6), and a base (7), the collector (5) and emitter (6) of each balancing transistor (4) connected in series with a respective circuit branch (2); a selection circuit (8) that connects the circuit branch (2) having the smallest current amongst the circuit branches (2) to the bases (7) of each balancing transistor; and an isolation circuit (9) that isolates circuit branches (2) having an open circuit fault from the rest of the target circuit (3). An associated method of balancing respective currents in a plurality of parallel circuit branches (2) in a target circuit (3) is also provided.

Abstract: Providing for a monolithic magnetic induction device having low DC resistance and small surface area is described herein. By way of example, the magnetic induction device can comprise a substrate (e.g., a semiconductor substrate) having trenches formed in a bottom layer of the substrate, and holes formed in the substrate between the trenches and an upper layer of the substrate. Additionally, the magnetic induction device can comprise a conductive coil embedded or deposited within the trenches. The magnetic induction device can further comprise a set of conductive vias formed in the holes that electrically connect the bottom layer of the substrate with the upper layer. Further, one or more integrated circuit components, such as active devices, can be formed in the upper layer, at least in part above the conductive coil. The vias can be utilized to connect to integrated circuit components with the conductive coil, where suitable.

Abstract: Provided is a current mirror circuit (1) for balancing respective currents in a plurality of parallel circuit branches (2) in a target circuit (3), the current mirror circuit (1) including: a plurality of balancing transistors (4), each having a connector (5), an emitter (6), and a base (7), the collector (5) and emitter (6) of each balancing transistor (4) connected in series with a respective circuit branch (2); a selection circuit (8) that connects the circuit branch (2) having the smallest current amongst the circuit branches (2) to the bases (7) of each balancing transistor; and an isolation circuit (9) that isolates circuit branches (2) having an open circuit fault from the rest of the target circuit (3). An associated method of balancing respective currents in a plurality of parallel circuit branches (2) in a target circuit (3) is also provided.

Abstract: The present invention provides a driver for LED lighting having a plurality of LEDs, the driver receiving AC input power from an AC power source and including a voltage multiplier for supplying a rectified output power to the LEDs to produce a luminous flux. Also provided is a method of driving LED lighting having a plurality of LEDs, the method including: receiving AC input power having an input voltage; multiplying the input voltage to supply a multiplied output voltage to the LEDs; and rectifying the AC input power to supply a rectified output power to the LEDs to produce a luminous flux.

Abstract: The present invention provides a passive LC ballast and an associated method of manufacturing a passive LC ballast for use with any one of a plurality of high voltage discharge lamps. The passive LC ballast has an inductance and a capacitance selected in accordance with one of a set of one or more inductance-capacitance pairs. Each inductance-capacitance pair defines a respective inductance and a respective capacitance such that, when the inductance and the capacitance of the passive LC ballast is selected in accordance with any one of the inductance-capacitance pairs and the passive LC ballast is used with any one of the lamps, the lamp operates between respective minimum and maximum lamp powers of the lamp.

Abstract: A full-bridge rectifier is configured to provide synchronous rectification with either a current-source or a voltage-source. The rectifier has an upper branch and a lower branch and two current loops, with each of the branches including voltage- or current-controlled active switches, diodes or combinations thereof that are selected such that each loop includes one active switch or diode from the upper branch and one active switch or diode from the lower branch, and each current loop comprises at least one diode or current-controlled active switch, and at least one voltage- or current-controlled active switch is included in one of the upper or lower branches.

Abstract: Various circuit configurations and topologies are provided for single and multi-phase, single-level or multi-level, full and half-bridge rectifiers in which diodes are replaced by combinations of voltage-controlled self-driven active switches, current-controlled self-driven active switches and inductors in order to reduce the effects of conduction loss in the diodes.

Abstract: The present invention provides an apparatus for wireless power transfer including three or more coils, each coil defining a respective coil plane, and the coils being arranged in one or more power flow paths whereby each coil can be magnetically coupled to one or more of the other coils thereby to wirelessly transfer power along the one or more power flow paths. The present invention also provides a method for wirelessly transferring power, the method including: providing three or more coils, each coil defining a respective coil plane; and arranging the coils in one or more power flow paths whereby each coil can be magnetically coupled to one or more of the other coils thereby to wirelessly transfer power along the one or more power flow paths.

Abstract: This invention is concerned with the control and design of a LED lighting system that does not need electrolytic capacitors in the entire system and can generate light output with reduced luminous flux fluctuation. The proposal is particularly suitable, but not restricted to, off-line applications in which the lighting system is powered by the ac mains. By eliminating electrolytic capacitors which have a limited lifetime of typically 15000 hours, the proposed system can be developed with passive and robust electrical components such as inductor and diode circuits, and it features long lifetime, low maintenance cost, robustness against extreme temperature variations and good power factor. No extra electronic control board is needed for the proposed passive circuits, which can become dimmable systems if the ac input voltage can be adjusted by external means.

Abstract: The present invention provides a passive LC ballast and an associated method of manufacturing a passive LC ballast for use with any one of a plurality of high voltage discharge lamps. The passive LC ballast has an inductance and a capacitance selected in accordance with one of a set of one or more inductance-capacitance pairs. Each inductance-capacitance pair defines a respective inductance and a respective capacitance such that, when the inductance and the capacitance of the passive LC ballast is selected in accordance with any one of the inductance-capacitance pairs and the passive LC ballast is used with any one of the lamps, the lamp operates between respective minimum and maximum lamp powers of the lamp.

Abstract: This invention provides an electronic control method for a planar inductive battery charging apparatus on which one or more electronic loads such as mobile phones, MP3 players etc can be placed and charged simultaneously. The power control circuit of the charging pad consists of two power conversion stages. Depending on the nature of the input power supply, the first power stage is an AC-DC power converter with variable output voltage control and a second stage is a DC-AC power inverter with constant current control. The combination of the two stages provides power control of the charging pad and generates AC magnetic flux of ideally constant magnitude over the charging areas within a group of primary windings that are excited.

Abstract: Providing for a monolithic magnetic induction device having low DC resistance and small surface area is described herein. By way of example, the magnetic induction device can comprise a substrate (e.g., a semiconductor substrate) having trenches formed in a bottom layer of the substrate, and holes formed in the substrate between the trenches and an upper layer of the substrate. Additionally, the magnetic induction device can comprise a conductive coil embedded or deposited within the trenches. The magnetic induction device can further comprise a set of conductive vias formed in the holes that electrically connect the bottom layer of the substrate with the upper layer. Further, one or more integrated circuit components, such as active devices, can be formed in the upper layer, at least in part above the conductive coil. The vias can be utilized to connect to integrated circuit components with the conductive coil, where suitable.

Abstract: An EMI filter for use between a power source and an electronic product is formed of at least one planar element including a pair of opposed coreless spiral planar windings, and a planar capacitor. This enables the integration of common mode and differential mode filters into integrated planar structures. Furthermore the planar EMI filter may be combined with an active filter element to provide a hybrid EMI filter comprising both passive and active elements with superior performance.

Abstract: LED illumination systems are formed with a suitable choice of LED and/or heatsink, such that an optimum operating power is identified using computer modeling for a desired output luminous flux, given the constraints of the rated power of the LED and the heatsink.

Abstract: Methods and principles are described for systematizing localized charging, load identification and bi-directional communication in a planar battery charging system. Also described is control circuitry for selectively energizing a primary winding when a load is placed on the platform. The optimization of the size of the receiver winding compared to the transmitter winding is discussed, while the associated communication methods include techniques for load identification, compatibility checks, hand-shaking and communication of charging status.

Abstract: This invention provides an electronic control method for a planar inductive battery charging apparatus on which one or more electronic loads such as mobile phones, MP3 players etc can be placed and charged simultaneously. The power control circuit of the charging pad consists of two power conversion stages. Depending on the nature of the input power supply, the first power stage is an AC-DC power converter with variable output voltage control and a second stage is a DC-AC power inverter with constant current control. The combination of the two stages provides power control of the charging pad and generates AC magnetic flux of ideally constant magnitude over the charging areas within a group of primary windings that are excited.