Automatic impedance matching using true power information

1. A dynamic impedance matching network comprising:

an impedance tuning network including a plurality of configurable elements;

a coupler in communication with a first node of the impedance tuning network;

a detector in communication with the coupler, the combination of the detector and the coupler configured to measure a first power value at the first node of the impedance tuning network; and

an automatic impedance tuner electrically coupled to the detector and configured to operate the plurality of configurable elements, the automatic impedance tuner including an optimization state machine configured to specify one or more configurable elements from the plurality of configurable elements to reconfigure based at least in part on the first power value.

2. The dynamic impedance matching network of claim 1 wherein the plurality of configurable elements include a plurality of switched capacitors.

3. The dynamic impedance matching network of claim 1 wherein the automatic impedance tuner is configured to reconfigure the one or more configurable elements by closing or opening at least one switch.

4. The dynamic impedance matching network of claim 1 wherein the impedance tuning network further includes an inductor having a first terminal coupled to the first node and positioned between a first set of the configurable elements and a second set of the configurable elements.

5. The dynamic impedance matching network of claim 1 wherein capacitance values for a first set of the configurable elements in communication with the first node match capacitance values for a second set of the configurable elements in communication with a second node of the impedance matching network.

6. The dynamic impedance matching network of claim 5 wherein the second node is a power amplifier output.

7. The dynamic impedance matching network of claim 1 wherein the impedance tuning network is configured to modify a load line impedance between a power amplifier and an antenna.

8. The dynamic impedance matching network of claim 1 wherein the impedance tuning network is in communication with a power amplifier at a second node of the impedance tuning network.

9. The dynamic impedance matching network of claim 8 wherein the automatic impedance tuner is further configured to obtain true power information for the power amplifier.

10. The dynamic impedance matching network of claim 9 wherein the automatic impedance tuner is configured to use the true power information in executing the state machine.

11. The dynamic impedance matching network of claim 1 wherein the automatic impedance tuner is further configured to determine an expected power for the power amplifier and use the expected power in executing the state machine.

12. The dynamic impedance matching network of claim 9 wherein the automatic impedance tuner is configured to obtain a true power of the power amplifier and determine the expected power by multiplying the true power by a power amplifier efficiency of the power amplifier.

13. The dynamic impedance matching network of claim 1 wherein the automatic impedance tuner reconfigures the one or more configurable elements based at least in part on a result of a comparison between an expected power and the first power value measured by the combination of the detector and the coupler.

14. A wireless device comprising:

a power amplifier module including a power amplifier; and

an impedance matching network including an impedance tuning network having a plurality of configurable elements, a coupler in communication with a first node of the impedance tuning network and the power amplifier in communication with a second node of the impedance tuning network, a detector in communication with the coupler, the combination of the detector and the coupler configured to measure a first power value at the first node of the impedance tuning network, and an automatic impedance tuner electrically coupled to the detector and configured to operate the plurality of configurable elements, the automatic impedance tuner including an optimization state machine configured to specify one or more configurable elements from the plurality of configurable elements to reconfigure based at least in part on the first power value.

15. The wireless device of claim 14 wherein the plurality of configurable elements include a plurality of switched capacitors and the automatic impedance tuner is configured to reconfigure the one or more configurable elements by closing or opening at least one switch.

16. The wireless device of claim 14 wherein the plurality of configurable elements are split into a first set of configurable elements in communication with a first node of an inductor and a second set of configurable elements in communication with a second node of the inductor, and a total capacitance of the first set of configurable elements matches a total capacitance of the second set of configurable elements.

17. The wireless device of claim 14 wherein the automatic impedance tuner is configured to determine an expected power output by the power amplifier based at least in part on a sense current, a supply voltage, and a power efficiency of the power amplifier.

18. The wireless device of claim 17 wherein the automatic impedance tuner reconfigures the one or more configurable elements based at least in part on a difference between the expected power and the first power value.

19. A method of performing dynamic impedance tuning, the method comprising:

determining an expected power for the power amplifier, the expected power calculated based on a collector current provided to the power amplifier, a collector voltage applied to the power amplifier, and an efficiency value for the power amplifier;

measuring an output power delivered to a load by the power amplifier;

determining whether the output power satisfies the expected power; and

responsive to determining that the output power does not satisfy the expected power, modifying a load line impedance for the power amplifier using an impedance tuning network.

20. The method of claim 19 wherein modifying the load line impedance includes adjusting a configuration of a plurality of configurable elements of an impedance tuning network based on an optimization state machine.