# US 11,309,849 B2 · Power amplifier circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,849 B2 - Document ID: US11309849B2 - Status: Granted - Kind: B2 - Application number: 16/935,514 - Filed: 2020-07-22 - Published: 2020-11-05 - Granted: 2022-04-19 - Earliest claimed: 2018-01-23 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Masatoshi Hase - Web page: https://patentgrep.com/patent/US11309849B2 ## CPC - H03F 1/3241: {using predistortion circuits (H03F1/3211, H03F1/3217 take precedence)} - H03F 1/3223: {using feed-forward (H03F1/3211 takes precedence)} - H03F 3/19: with semiconductor devices only - H03F 3/245: {with semiconductor devices only} - H03F 2200/171: A filter circuit coupled to the output of an amplifier - H03F 2200/451: the amplifier being a radio frequency amplifier - H03F: AMPLIFIERS ## Abstract Provided is a power amplifier circuit that can increase output power and also reduce the effect of intermodulation distortion. The power amplifier circuit includes a power divider, a distortion compensation circuit provided on the secondary path, a power combiner, and a first amplifier configured. The distortion compensation circuit includes a generation circuit configured to generate the second-harmonic wave of the input signal, a filter circuit configured to attenuate the fundamental wave and pass the second-harmonic wave, and a phase adjustment circuit configured to adjust the phase of the second-harmonic wave. ## Claims ### Claim 1 A power amplifier circuit comprising: a power divider configured to divide an input signal, and to output the divided input signal to a primary path and a secondary path; a distortion compensation circuit in the secondary path; a power combiner configured to combine a fundamental wave of the input signal from the primary path with a second-harmonic wave of the input signal from the secondary path; and a first amplifier configured to amplify a combined signal outputted from the power combiner, and to output an amplified signal, wherein the distortion compensation circuit comprises: a generation circuit configured to generate the second-harmonic wave of the input signal, a filter circuit configured to attenuate the fundamental wave and to pass the second-harmonic wave, and a phase adjustment circuit configured to adjust a phase of the second-harmonic wave, wherein the distortion compensation circuit further comprises a second amplifier configured to amplify an amplitude of the second-harmonic wave, and wherein the second amplifier is between the generation circuit and the phase adjustment circuit. ### Claim 2 (depends on 1) The power amplifier circuit according to claim 1, wherein the second amplifier is configured to amplify the amplitude of the second-harmonic wave such that a signal obtained as a difference between the second-harmonic wave and the fundamental wave cancels, at an output of the first amplifier, a third-order intermodulation distortion occurring in the first amplifier. ### Claim 3 (depends on 1) The power amplifier circuit according to claim 1, wherein the phase adjustment circuit is configured to change the phase of the second-harmonic wave such that a signal obtained as a difference between the second-harmonic wave and the fundamental wave is substantially antiphase with, at an output of the first amplifier, a third-order intermodulation distortion occurring in the first amplifier. ### Claim 4 (depends on 2) The power amplifier circuit according to claim 2, wherein the phase adjustment circuit is configured to change the phase of the second-harmonic wave such that the signal obtained as the difference between the second-harmonic wave and the fundamental wave is substantially antiphase with, at the output of the first amplifier, the third-order intermodulation distortion occurring in the first amplifier. ### Claim 5 (depends on 1) The power amplifier circuit according to claim 1, further comprising: a third amplifier in a stage preceding the power divider, the third amplifier being configured to output the input signal; and a second-harmonic-wave attenuation circuit between the power divider and the power combiner in the primary path, the second harmonic-wave attenuation circuit being configured to attenuate a signal in a frequency range of the second-harmonic wave. ### Claim 6 (depends on 3) The power amplifier circuit according to claim 3, further comprising: a third amplifier in a stage preceding the power divider, the third amplifier being configured to output the input signal; and a second-harmonic-wave attenuation circuit between the power divider and the power combiner in the primary path, the second harmonic-wave attenuation circuit being configured to attenuate a signal in a frequency range of the second-harmonic wave. ### Claim 7 (depends on 5) The power amplifier circuit according to claim 5, wherein the second-harmonic-wave attenuation circuit comprises a fourth amplifier configured to amplify the input signal outputted to the primary path by the power divider. ### Claim 8 (depends on 1) The power amplifier circuit according to claim 1, wherein the filter circuit is arranged outside a semiconductor chip at which the first amplifier is arranged. ### Claim 9 A power amplifier circuit comprising: a power divider configured to divide an input signal, and to output the divided input signal to a primary path and a secondary path; a distortion compensation circuit in the secondary path; a power combiner configured to combine a fundamental wave of the input signal from the primary path with a second-harmonic wave of the input signal from the secondary path; and a first amplifier configured to amplify a combined signal outputted from the power combiner, and to output an amplified signal; a third amplifier in a stage preceding the power divider, the third amplifier being configured to output the input signal; and a second-harmonic-wave attenuation circuit between the power divider and the power combiner in the primary path, the second harmonic-wave attenuation circuit being configured to attenuate a signal in a frequency range of the second-harmonic wave, wherein the distortion compensation circuit comprises: a generation circuit configured to generate the second-harmonic wave of the input signal, a filter circuit configured to attenuate the fundamental wave and to pass the second-harmonic wave, and a phase adjustment circuit configured to adjust a phase of the second-harmonic wave. ### Claim 10 (depends on 9) The power amplifier circuit according to claim 9, wherein the phase adjustment circuit is configured to change the phase of the second-harmonic wave such that a signal obtained as a difference between the second-harmonic wave and the fundamental wave is substantially antiphase with, at an output of the first amplifier, a third-order intermodulation distortion occurring in the first amplifier. ### Claim 11 (depends on 9) The power amplifier circuit according to claim 9, wherein the second-harmonic-wave attenuation circuit comprises a fourth amplifier configured to amplify the input signal outputted to the primary path by the power divider.