# US 2014/0191807 A1 · Systems and methods for biasing amplifiers with adaptive closed loop control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191807 A1 - Document ID: US20140191807A1 - Status: Published application - Kind: A1 - Application number: 14/150,721 - Filed: 2014-01-08 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: Aviat U.S., Inc. - Applicants: Aviat U.S., Inc. - Inventors: Youming Qin; Frank Matsumoto; Andres Goytia; Cuong Nguyen - Web page: https://patentgrep.com/patent/US20140191807A1 ## CPC - H03F 3/21: with semiconductor devices only {(H03F3/245 takes precedence)} - H03F 1/0261: {with control of the polarisation voltage or current, e.g. gliding Class A} - H03F 3/19: with semiconductor devices only - H03F 3/245: {with semiconductor devices only} - H03F: AMPLIFIERS ## Abstract Various embodiments described herein provide systems and methods for improved performance for power amplifiers, particularly GaN power amplifiers. According to some embodiments, a power amplifier (e.g., GaN power amplifier) utilizes an adaptive closed loop control of the drain current of the power amplifier to achieve improved performance for the power amplifier. ## Claims ### Claim 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. ### Claim 2 (depends on 1) The system of claim 1, wherein the operational parameter comprises a plurality of operational parameters. ### Claim 3 (depends on 1) The system of claim 1, wherein the power amplifier is a GaN power amplifier. ### Claim 4 (depends on 1) The system of claim 1, wherein the operational parameter comprises a frequency of an input signal of the power amplifier, a phase of the input signal of the power amplifier, a power level of the input signal of the power amplifier, or a temperature of the power amplifier. ### Claim 5 (depends on 1) The system of claim 1, wherein storing the optimized quiescent drain current value comprises storing the optimized quiescent drain current value in association with the operational parameter. ### Claim 6 (depends on 1) The system of claim 1, wherein 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. ### Claim 7 (depends on 1) The system of claim 1, wherein the condition is that a difference between the drain current and the particular drain current value from the saved drain current data is less than, equal to, or larger than a predetermined value. ### Claim 8 (depends on 1) The system of claim 1, wherein adjusting the drain current based on the calibrated drain current comprises adjusting the drain current to match or substantially match the particular drain current value from the saved drain current data. ### Claim 9 (depends on 1) The system of claim 1, wherein adjusting the drain current based on the calibrated drain current comprises adjusting a voltage bias of the power amplifier such that the drain current matches or substantially matches the particular drain current value from the saved drain current data. ### Claim 10 (depends on 1) 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. ### Claim 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. ### Claim 12 (depends on 11) The method of claim 11, wherein the operational parameter comprises a plurality of operational parameters. ### Claim 13 (depends on 11) The method of claim 11, wherein the power amplifier is a GaN power amplifier. ### Claim 14 (depends on 11) The method of claim 11, wherein the operational parameter comprises a frequency of an input signal of the power amplifier, a phase of the input signal of the power amplifier, a power level of the input signal of the power amplifier, or a temperature of the power amplifier. ### Claim 15 (depends on 11) The method of claim 11, wherein storing the optimized quiescent drain current value comprises storing the optimized quiescent drain current value in association with the operational parameter. ### Claim 16 (depends on 11) The method of claim 11, wherein 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. ### Claim 17 (depends on 11) The method of claim 11, wherein the condition is that a difference between the drain current and the particular drain current value from the saved drain current data is less than, equal to, or larger than a predetermined value. ### Claim 18 (depends on 11) The method of claim 11, wherein adjusting the drain current based on the calibrated drain current comprises adjusting the drain current to match or substantially match the particular drain current value from the saved drain current data. ### Claim 19 (depends on 11) The method of claim 11, wherein adjusting the drain current based on the calibrated drain current comprises adjusting a voltage bias of the power amplifier such that the drain current matches or substantially matches the particular drain current value from the saved drain current data. ### Claim 20 (depends on 11) 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. ### Claim 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 saved drain current data if the condition is determined to be satisfied.