INDUCTIVELY COUPLED BALLAST CIRCUIT

摘要

A ballast circuit is disclosed for inductively providing power to a load. The ballast circuit includes an oscillator, a driver, a switching circuit, a resonant tank circuit and a current sensing circuit. The current sensing circuit provides a current feedback signal to the oscillator that is representative of the current in the resonant tank circuit. The current feedback signal drives the frequency of the ballast circuit causing the ballast circuit to seek resonance. The ballast circuit preferably includes a current limit circuit that is inductively coupled to the resonant tank circuit. The current limit circuit disables the ballast circuit when the current in the ballast circuit exceeds a predetermined threshold or falls outside a predetermined range.

主权项

1. A non-contact power transfer system for transferring power inductively comprising:
an electronic device separable from a non-contact power supply, said electronic device being absent from physical interconnection with said non-contact power supply and absent from electrical connection with said non-contact power supply, said electronic device and said non-contact power supply capable of inductively coupling when in sufficient proximity to each other to transfer power inductively, said electronic device including:
a secondary absent from physical interconnection with said non-contact power supply, said secondary being absent from electrical connection with said non-contact power supply;a load electrically connected to said secondary, whereby power is provided to said load by said secondary; and said non-contact power supply including:
a primary circuit having a primary configured to inductively couple with said secondary of said electronic device to transfer power inductively to said electronic device;a radio frequency system configured to receive information communicated from said electronic device;a sensor configured to sense a characteristic of power in said non-contact power supply, said characteristic of power being affected by a characteristic of said load reflected through inductive coupling between said primary and said secondary;a control system operably coupled to said primary circuit, said radio frequency system, and said sensor, said control system configured to control supply of power to said primary to affect an amount of power transferred to said secondary, said control system configured to obtain, via said radio frequency system, information from said electronic device regarding operation of said electronic device, said control circuit varying an operational characteristic of said power supplied to said primary based on said characteristic of power sensed by said sensor; whereby said electronic device is readily placeable in sufficient proximity to said non-contact power supply to inductively receive power without the need to make electrical connection with said non-contact power supply and without the need to make physical interconnection with said non-contact power supply; and whereby said electronic device is readily removable from the sufficient proximity of said non-contact power supply without the need to disconnect electrical connection with said non-contact power supply and without the need to disconnect physical interconnection with said non-contact power supply.