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:
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:
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:
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:
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:
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:
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:
An electronic ballast is disclosed that is capable of operating with any fluorescent lamp within a range of nominal operating powers. The electronic ballast is capable of sensing the power rating of the lamp from the peak lamp voltage, and provides for varying the switching frequency of the ballast depending on the power rating of the lamp.
Abstract:
Novel designs for printed circuit board transformers, and in particular for coreless printed circuit board transformers designed for operation in power transfer applications, are disclosed in which shielding is provided by a combination of ferrite plates and thin copper sheets.
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.