Systems and methods for biasing amplifiers with adaptive closed loop control

1. A system comprising:

a power amplifier having an output signal and a drain current;

a power amplifier calibration module configured to determine an optimized quiescent drain current value for the drain current while the power amplifier is operating under an operational parameter, and determine a set of calibrated drain current values for the drain current, the set of calibrated drain current values being calibrated for a set of power levels for the output signal while the power amplifier is operating under the operational parameter;

a storage module configured to store the optimized quiescent drain current value and the set of calibrated drain current values as saved drain current data; and

a power amplifier operation module configured to compare the drain current to a particular drain current value in the saved drain current data, determine whether the comparison satisfies a condition, and adjust the drain current based on the particular drain current value if the condition is determined to be satisfied.

2. The system of claim 1 , wherein the operational parameter comprises a plurality of operational parameters.

3. The system of claim 1 , wherein the power amplifier is a GaN power amplifier.

4. The system of claim 1 , wherein the operational parameter comprises a frequency of an input signal of the power amplifier, a phase of an input signal of the power amplifier, a power level of an input signal of the power amplifier, or a temperature of the power amplifier.

5. The system of claim 1 , wherein the storing the optimized quiescent drain current value comprises storing the optimized quiescent drain current value in association with the operational parameter.

6. The system of claim 1 , wherein the storing the set of calibrated drain current values comprises storing the set of calibrated drain current values in association with the operational parameter or the set of power levels.

7. The system of claim 1 , wherein the condition is that a difference between the present drain current value and the particular drain current value in the saved drain current data is less than, equal to, or larger than a predetermined value.

8. The system of claim 1 , wherein the adjusting the drain current based on the particular drain current value comprises adjusting the drain current to match or substantially match the particular drain current value in the saved drain current data.

9. The system of claim 1 , wherein the adjusting the drain current based on the particular drain current value comprises adjusting a voltage bias of the power amplifier such that the drain current matches or substantially matches the particular drain current value in the saved drain current data.

10. The system of claim 1 , wherein the particular drain current value is associated with a present operational parameter under which the power amplifier is presently operating.

11. A method comprising:

determining an optimized quiescent drain current value for a drain current of a power amplifier while the power amplifier is operating under an operational parameter;

storing the optimized quiescent drain current value as saved drain current data;

determining a set of calibrated drain current values for the drain current, the set of calibrated drain current values being calibrated for a set of power levels for an output signal of the power amplifier while the power amplifier is operating under the operational parameter;

storing the set of calibrated drain current values in the saved drain current data;

comparing the drain current to a particular drain current value in the saved drain current data;

determining whether the comparison satisfies a condition; and

adjusting the drain current based on the particular drain current value if the condition is determined to be satisfied.

12. The method of claim 11 , wherein the operational parameter comprises a plurality of operational parameters.

13. The method of claim 11 , wherein the power amplifier is a GaN power amplifier.

14. The method of claim 11 , wherein the operational parameter comprises a frequency of an input signal of the power amplifier, a phase of an input signal of the power amplifier, a power level of an input signal of the power amplifier, or a temperature of the power amplifier.

15. The method of claim 11 , wherein the storing the optimized quiescent drain current value comprises storing the optimized quiescent drain current value in association with the operational parameter.

16. The method of claim 11 , wherein the storing the set of calibrated drain current values comprises storing the set of calibrated drain current values in association with the operational parameter or the set of power levels.

17. The method of claim 11 , wherein the condition is that a difference between the present drain current value and the particular drain current value in the saved drain current data is less than, equal to, or larger than a predetermined value.

18. The method of claim 11 , wherein the adjusting the drain current based on the particular drain current value comprises adjusting the drain current to match or substantially match the particular drain current value in the saved drain current data.

19. The method of claim 11 , wherein the adjusting the drain current based on the particular drain current value comprises adjusting a voltage bias of the power amplifier such that the drain current matches or substantially matches the particular drain current value in the saved drain current data.

20. The method of claim 11 , wherein the particular drain current value is associated with a present operational parameter under which the power amplifier is presently operating.

21. A system comprising:

means for determining an optimized quiescent drain current value for a drain current of a power amplifier while the power amplifier is operating under an operational parameter;

means for storing the optimized quiescent drain current value as saved drain current data;

means for determining a set of calibrated drain current values for the drain current, the set of calibrated drain current values being calibrated for a set of power levels for an output signal of the power amplifier while the power amplifier is operating under the operational parameter;

means for storing the set of calibrated drain current values in the saved drain current data;

means for comparing the drain current to a particular drain current value in the saved drain current data;

means for determining whether the comparison satisfies a condition; and

means for adjusting the drain current based on the particular drain current value if the condition is determined to be satisfied.