An adaptive inductive ballast is provided with the capability to communicate with a remote device powered by the ballast. To improve the operation of the ballast, the ballast changes its operating characteristics based upon information received from the remote device. Further, the ballast may provide a path for the remote device to communicate with device other than the adaptive inductive ballast.

Adaptive inductive power supply with communication

A contactless power supply has a dynamically configurable tank circuit powered by an inverter. The contactless power supply is inductively coupled to one or more loads. The inverter is connected to a DC power source. When loads are added or removed from the system, the contactless power supply is capable of modifying the resonant frequency of the tank circuit, the inverter frequency, the inverter duty cycle or the rail voltage of the DC power source.

Adaptive inductive power supply

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.

Inductively coupled ballast circuit

An inductive power supply that maintains resonance and adjusts duty cycle based on feedback from a secondary circuit. A controller, driver circuit and switching circuit cooperate to generate an AC signal at a selected operating frequency and duty cycle. The AC signal is applied to the tank circuit to create an inductive field for powering the secondary. The secondary communicates feedback about the received power back to the primary controller. The power transfer efficiency may be optimized by maintaining the operating frequency substantially at resonance, and the amount of power transferred may be controlled by adjusting the duty cycle.

Inductive power supply with duty cycle control

The present configuration provides an integrated wireless power system for powering or charging a portable device. The integrated wireless power system includes 1) an integrated wireless power appliance that both provides power as well as additional functionality, such as timekeeping, radio, and alarm functionality and 2) a portable device capable of receiving wireless power from the integrated wireless power appliance.

Integrated wireless power system

A low leakage inductance, versatile RF transformer with multiple input/output voltage ratios. The transformer has many applications. For example, and not by way of limitation, the transformer can be used with switching power supplies, RF induction power supplies, and RF plasma power supplies. The efficiency of the transformer is on the order of 99% to 99.7%. These efficiencies have been measured at power levels of 3 kilowatts (KW) to 10 KW.

Leslie L. Thompson

Papers

Efficient, low leakage inductance, multi-tap, RF transformer and method of making same