Abstract: Systems, methods, and devices that employ self-driven gate-drive circuitry to facilitate controlling power switches to emulate a diode bridge to synchronously rectify a power signal are presented. A single-phase or multi-phase synchronous rectifier can comprise at least a first pair of switches of a first conducting path and a second pair of switches of a second conducting path that can form or emulate a diode bridge. To facilitate emulating turn-on and turn-off conditions of a diode, a switch can be turned on when voltage across the switch is forward-biased and turned off when switch current is reversed; also, there can be at least one current-controlled switch in each conducting path. Self-driven gate-drive circuitry employs low power components that can facilitate controlling respective switching of the at least first pair and second pair of switches, wherein switching of the switches is also controlled at start-up to emulate a diode bridge.

Abstract: An LED driver for a plurality of LED light strings has a common node and a plurality of driver output nodes for connection of a plurality of LED light strings. A master power circuit is provided and has a master output connected with the common node. A plurality of slave power circuits are provided which each have a slave output connected with a respective one of the driver output nodes.

Abstract: This invention is related to a novel method and apparatus that provides selective and enhanced power flow in wireless power transfer systems with multiple receivers. Auxiliary circuits are introduced in the receiver circuits (and relay circuits if applicable) so as to ensure proper frequency-selective wireless power flow to the appropriate targeted receivers, with the pickup power by the non-targeted receivers substantially reduced even if the chosen tuned frequencies for different receivers are not widely apart.

Abstract: Methods and numerical tools for designing and optimizing LED systems are provided to achieve a desired luminous performance and to increase reliability and operating lifetime. In addition, methods for designing LED illumination systems are also disclosed to determine an optimum operating power for a desired output luminous flux, given the condition of the rated power of the LED and the heatsink. By the invention, LED illumination systems can be designed with a suitable choice of LED and/or heatsink.

Abstract: A power compensator for compensating voltage at a location along a power transmission line, the compensator having a controller for controlling a voltage generated across the compensator, wherein the voltage is controlled to maintain a power transmission line voltage at a value dependent on the power transmission line location.

Abstract: Systems, methods, and devices that employ self-driven gate-drive circuitry to facilitate controlling power switches to emulate a diode bridge to synchronously rectify a power signal are presented. A single-phase or multi-phase synchronous rectifier can comprise at least a first pair of switches of a first conducting path and a second pair of switches of a second conducting path that can form or emulate a diode bridge. To facilitate emulating turn-on and turn-off conditions of a diode, a switch can be turned on when voltage across the switch is forward-biased and turned off when switch current is reversed; also, there can be at least one current-controlled switch in each conducting path. Self-driven gate-drive circuitry employs low power components that can facilitate controlling respective switching of the at least first pair and second pair of switches, wherein switching of the switches is also controlled at start-up to emulate a diode bridge.

Abstract: There is provided a planar inductive battery charging system designed to enable electronic devices to be recharged. The system includes a planar charging module having a charging surface on which a device to be recharged is placed. Within the charging module and parallel to the charging surface is at least one and preferably an array of primary windings that couple energy inductively to a secondary winding formed in the device to be recharged. The invention also provides secondary modules that allow the system to be used with conventional electronic devices not formed with secondary windings.

Abstract: There is provided a planar inductive battery charging system designed to enable electronic devices to be recharged. The system includes a planar charging module having a charging surface on which a device to be recharged is placed. Within the charging module and parallel to the charging surface is at least one and preferably an array of primary windings that couple energy inductively to a secondary winding formed in the device to be recharged. The invention also provides secondary modules that allow the system to be used with conventional electronic devices not formed with secondary windings.

Abstract: Systems, methods, and devices that employ self-driven gate-drive circuitry to facilitate controlling power switches to emulate a diode bridge to synchronously rectify a power signal are presented. A single-phase or multi-phase synchronous rectifier can comprise at least a first pair of switches of a first conducting path and a second pair of switches of a second conducting path that can form or emulate a diode bridge. To facilitate emulating turn-on and turn-off conditions of a diode, a switch can be turned on when voltage across the switch is forward-biased and turned off when switch current is reversed; also, there can be at least one current-controlled switch in each conducting path. Self-driven gate-drive circuitry employs low power components that can facilitate controlling respective switching of the at least first pair and second pair of switches, wherein switching of the switches is also controlled at start-up to emulate a diode bridge.

Abstract: The present invention provides a current balancing circuit and method for balancing the respective currents in a plurality of parallel circuit branches in a target circuit. The current balancing circuit including: a plurality of balancing transistors, each having a collector, an emitter, and a base, the collector and emitter of each balancing transistor connected in series with a respective circuit branch; and a selection circuit for selectively connecting the circuit branch having the smallest current amongst the circuit branches to the bases of each balancing transistor.

Abstract: The present invention provides a portable electronic device including an antenna having a major planar cross-section, and a power transfer coil having windings parallel to a coil plane, the coil plane extending to the perimeter of the power transfer coil. The antenna and the power transfer coil are arranged such that the major planar cross-section is substantially perpendicular to the coil plane if a line directed perpendicularly from the coil plane intersects the major planar cross-section. An associated method of assembling a portable electronic device is also provided.

Abstract: A family of power converters has input ac voltage regulation instead of output dc voltage regulation. The bi-directional converters control power flows and maintain the input ac voltage at or close to a certain reference value. These bi-directional power converters handle both active and reactive power while maintaining the input ac voltage within a small tolerance. Use of these converters is favorable for future power grid maintenance in that they (i) ensure the load demand follows power generation and (ii) provide distributed stability support for the power grid. The converters can be used in future smart loads that help stabilize the power grid.

Abstract: An LED driver for a plurality of LED light strings has a common node and a plurality of driver output nodes for connection of a plurality of LED light strings. A master power circuit is provided and has a master output connected with the common node. A plurality of slave power circuits are provided which each have a slave output connected with a respective one of the driver output nodes.

Abstract: There is provided a power system designed to enable electronic devices to be powered. The system includes a planar surface on which a device to be powered is placed. Within the power system and substantially parallel to the planar surface are multiple primary transformer windings formed in a multi-layer structure that couple energy inductively to a secondary winding formed in the device to be powered. A winding of a second layer is offset relative to a winding of a first layer.

Abstract: There is provided a power system designed to enable electronic devices to be powered. The system includes a planar surface on which a device to be powered is placed. Within the power system and substantially parallel to the planar surface are multiple primary transformer windings formed in a multi-layer structure that couple energy inductively to a secondary winding formed in the device to be powered. A winding of a second layer is offset relative to a winding of a first layer.

Abstract: This invention relates to an apparatus and method for deriving speed and position information for an electric motor. Apparatus for and a method of controlling a motor 100 are also disclosed. The apparatus for providing information relating to the operation of an electrical motor 100 comprises a sampler 50, 51 for sampling the instantaneous motor current is and a processor 160 for determining the instantaneous rate of change of the motor current and providing information about the motion or position of said motor based on said instantaneous rate of change of the motor current. In this way speed and position information can be provided, at low speeds, and without using a speed sensor.

Abstract: The present invention provides a current balancing circuit and method for balancing the respective currents in a plurality of parallel circuit branches in a target circuit. The current balancing circuit including: a plurality of balancing transistors, each having a collector, an emitter, and a base, the collector and emitter of each balancing transistor connected in series with a respective circuit branch; and a selection circuit for selectively connecting the circuit branch having the smallest current amongst the circuit branches to the bases of each balancing transistor.

Abstract: The Present Invention Provides an Antenna Network for Passively or Actively enhancing signal transmission or reception of one or more portable transceiver devices. The antenna network includes one or more antennas, each having a coupling portion and a radiating portion, the coupling portion being distributed across a coupling area and the radiating portion being located away from the coupling area, whereby signal transmission or reception of the one or more portable transceiver devices can occur through the radiating portion when the one or more portable transceiver devices are located within the coupling area.

Abstract: There is provided a planar inductive battery charging system designed to enable electronic devices to be recharged. The system includes a planar charging module having a charging surface on which a device to be recharged is placed. Within the charging module and substantially parallel to the charging surface are multiple primary windings formed in a multi-layer structure that couple energy inductively to a secondary winding formed in the device to be recharged. A winding of a first layer is offset relative to a winding of a second layer. The invention also provides secondary modules that allow the system to be used with conventional electronic devices not formed with secondary windings.

Abstract: The present invention provides an AC-DC converter and AC-DC conversion method for converting an AC input provided by a power transfer winding. The AC-DC converter includes a rectifying means for rectifying the AC input into a rectified output, and a control means for controlling the rectifying means based on a comparison between a reference signal and a voltage feedback signal, the voltage feedback signal being based on the rectified output.