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: Disclosed is an AC-AC power converter with multiple AC voltage output branches. The AC-AC power converter is bridgeless and contains only one power stage. The AC-AC power converter consists of only one inductor for power conversion and provides a current source for successively feeding multiple output branches one at a time. Each output branch can be selected by the corresponding switch and its resonant circuit turns the input current source into an AC power source.

Abstract: Disclosed is an AC-AC power converter with multiple AC voltage output branches. The AC-AC power converter is bridgeless and contains only one power stage. The AC-AC power converter consists of only one inductor for power conversion and provides a current source for successively feeding multiple output branches one at a time. Each output branch can be selected by the corresponding switch and its resonant circuit turns the input current source into an AC power source.

Abstract: A power converter circuit includes: a direct current (DC) side; a first passive network; a first current switching network; at least one floating capacitor; a second current switching network; a second passive network; and an alternating current (AC) side. The first passive network is connected between the DC side and the first current switching network for linking the DC side and the first current switching network. The first current switching network comprises at least four serially linked switches for switching the power converter circuit between switching cycles. The at least one floating capacitor is connected to the first current switching network. The second current switching network comprises two pairs of switches for providing an interface between the first current switching network and the second passive network. The second passive network is connected between the second current switching network and the AC side.

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: Wireless power transfer systems and methods are provided. No wireless communication system is necessary feedback output information from the receiver side to the transmitter side. Nor is any knowledge of the mutual coupling or mutual inductance between the transmitter side and the receiver side required. A system can include an intermediate capacitor in the receiver circuit as a power flow indicator and hysteresis on-off switching actions of a decoupling power switch in the receiver circuit to regulate the DC voltage of the intermediate capacitor (for voltage-control) and the load current (for current-control) at a rated value within a narrow tolerance band. The turn-on and turn-off times of the decoupling switch in the receiver circuit can be detected in the transmitter circuit from, for example, the primary winding current or voltage. This can be used to meet the power demand in the receiver circuit dynamically.

Abstract: A method for identifying impedance related parameters in a wireless power transfer (WPT) system including n coils is disclosed. Said method includes determining optimum values of the impedance related parameters based on a set of measured input impedance by applying an evolutionary algorithm to solve optimum solutions. Wherein the set of measured input impedance includes an input impedance vector {right arrow over (Z)}=(Z1, Z2, . . . , Zm?1, Zm), each input impedance in the vector (Zk) measured at different frequencies fk, (k=1, 2, . . . m); and the impedance related parameters includes dll?1 representing a distance between the l-th coil and the l+1 coil (l=1, 2, . . . n?1) and Ci representing a capacitance of the capacitor connected to the i-th coil (i=1, 2, . . . n).

Abstract: A single-stage AC-DC single-inductor multiple-output (SIMO) LED driver uses a single inductor (L) to drive multiple independent LED strings (341-34n) with Power Factor Correction (PFC). The driver uses a diode bridge (20) to achieve initial AC to DC conversion. The output of the bridge (20) is provided to a buck converter whose output is shared with multiple LED strings by a time division multiplex circuit. Feedback is used to separately control the current supplied to each LED string by using a separate reference for each string and controlling the width of the current pulse provided to a string. Current balancing in every LED string can be achieved with the same voltage reference without the need for additional circuitry.

Abstract: Wireless power transfer systems and methods are provided. No wireless communication system is necessary feedback output information from the receiver side to the transmitter side. Nor is any knowledge of the mutual coupling or mutual inductance between the transmitter side and the receiver side required. A system can include an intermediate capacitor in the receiver circuit as a power flow indicator and hysteresis on-off switching actions of a decoupling power switch in the receiver circuit to regulate the DC voltage of the intermediate capacitor (for voltage-control) and the load current (for current-control) at a rated value within a narrow tolerance band. The turn-on and turn-off times of the decoupling switch in the receiver circuit can be detected in the transmitter circuit from, for example, the primary winding current or voltage. This can be used to meet the power demand in the receiver circuit dynamically.

Abstract: A single-stage AC-DC single-inductor multiple-output (SIMO) LED driver uses a single inductor (L) to drive multiple independent LED strings (341-34n) with Power Factor Correction (PFC). The driver uses a diode bridge (20) to achieve initial AC to DC conversion. The output of the bridge (20) is provided to a buck converter whose output is shared with multiple LED strings by a time division multiplex circuit. Feedback is used to separately control the current supplied to each LED string by using a separate reference for each string and controlling the width of the current pulse provided to a string. Current balancing in every LED string can be achieved with the same voltage reference without the need for additional circuitry.

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: A method for identifying impedance related parameters in a wireless power transfer (WPT) system including n coils is disclosed. Said method includes determining optimum values of the impedance related parameters based on a set of measured input impedance by applying an evolutionary algorithm to solve optimum solutions. Wherein the set of measured input impedance includes an input impedance vector {right arrow over (Z)}=(Z1, Z2, . . . , Zm-1, Zm), each input impedance in the vector (Zk) measured at different frequencies fk, (k=1, 2, . . . m); and the impedance related parameters includes dll+1 representing a distance between the l-th coil and the l+1 coil (l=1, 2, . . . n?1) and Ci representing a capacitance of the capacitor connected to the i-th coil (i=1, 2, . . . n).

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: 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.