System and method for powering a load

• US 20070086225A1
• Filed: 10/14/2005
• Published: 04/19/2007
• Est. Priority Date: 10/14/2005
• Status: Active Grant

• Current Assignee: Philips IP Ventures B.V. (Koninklijke Philips N.V.)
• Original Assignee: Access Business Group International LLC (Alticor Incorporated)
• Inventors: Lord, John, Bachman, Wesley, Baarman, David
• Granted Patent: US 7,382,636 B2
• Time in Patent Office: Days
• US Class Current: 363/131
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02M 7/4815 Resonant converters H02M7/4811 and H02M7/4826 take precedence
• CPC Class Codes: H02M 7/53803 with automatic control of output voltage or current
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A power supply for inductively powering a remote device has an inverter operating at an operating frequency and a primary coil. A phase comparator compares the phase of the voltage or current delivered by the power supply. If the phase relationship detected by the comparator is unacceptable, the inverter is disabled. After a period of time, the inverter is re-enabled, and the phase relationship is again determined.

Claims

1. A circuit for powering a remote device comprising:

an inverter operating at the operating frequency;

a tank circuit;

an inductor for transferring power to the remote device;

a phase comparator for comparing the phase of the voltage supplied to the tank circuit with the phase of the voltage supplied to the inductor; and

a disabling means for disabling the inverter if the phase of the voltage supplied to the inductor and the phase of the voltage supplied to the tank circuit are out of phase by a predetermined amount.

2. The circuit of claim 1 where the inverter further comprises a first switch.

3. The circuit of claim 2 where the inverter further comprises a driver coupled to the switch.

4. The circuit of claim 3 where the inverter further comprises an oscillator for operating the switch at the operating frequency.

5. The circuit of claim 4 further comprising a receiver for receiving phase information from the remote device regarding the operating phase.

6. The circuit of claim 5 where the information is an identifying code and the processor.

7. The circuit of claim 6 where the circuit has a second switch.

8. The circuit of claim 7 where the first switch and the second switch are arranged in series.

9. The circuit of claim 8 where the disabling means is a processor.

10. The circuit of claim 8 where the disabling means is an analog circuit.

11. The circuit of claim 8 where the disabling means is a digital circuit.

12. A method of operating a circuit comprising:

operating an inverter at a first frequency;

determining a first operating phase of the inverter; and

if the first operating phase is unacceptable, then disabling the inverter.

13. The method of claim 12 where the inverter includes an oscillator, and the step of disabling the inverter includes disabling the oscillator.

14. The method of claim 13 further comprising:

comparing the first operating phase with a preferred operating phase.

15. The method of claim 14 further comprising:

if the inverter is disabled, waiting for a period of time;

operating the inverter at a second frequency;

determining a second operating phase of the inverter;

if the second operating phase is unacceptable, then disabling the inverter.

16. The method of claim 15 where the first frequency is the same as the second frequency.

17. The method of claim 15 where the first frequency is different from the second frequency.