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 comprising:
a non-contact power supply including:
a primary subcircuit having a primary;a sensor configured to sense a characteristic of power that changes over time, said sensor configured to provide a first sensor output indicative of said characteristic of power at a first time, said sensor configured to provide a second sensor output indicative of said characteristic of power at a second time different from said first time.a control circuit supplying power to said primary, said control circuit making an adjustment of an operational characteristic of said non-contact power supply based on both said first sensor output and said second sensor output;an electronic device separable from said 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 said electronic device includes:
a secondary for inductively coupling with said primary, said secondary being absent from physical interconnection with said primary, said secondary being absent from electrical connection with said primary, wherein said primary is capable of inductively energizing said secondary; anda load electrically connected to said secondary, whereby power is provided to said load by said secondary,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, andwhereby 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.