# US 12,184,245 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 12,184,245 B2 - Document ID: US12184245B2 - Status: Granted - Kind: B2 - Application number: 17/410,003 - Filed: 2021-08-24 - Published: 2022-03-03 - Granted: 2024-12-31 - Earliest claimed: 2020-08-25 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Jun Enomoto; Yuri Honda; Satoshi Tanaka; Fumio Harima - Web page: https://patentgrep.com/patent/US12184245B2 ## CPC - H03F 1/30: Modifications of amplifiers to reduce influence of variations of temperature or supply voltage {or other physical parameters (in differential amplifiers H03F3/45479)} - H03F 3/211: {using a combination of several amplifiers (H03F3/60 takes precedence)} - H03F 1/0211: {with control of the supply voltage or current} - H03F 1/565: {using inductive elements} - H03F 3/19: with semiconductor devices only - H03F 2200/222: A circuit being added at the input of an amplifier to adapt the input impedance of the amplifier - H03F 2200/267: A capacitor based passive circuit, e.g. filter, being used in an amplifying circuit - H03F 2200/318: A matching circuit being used as coupling element between two amplifying stages - H03F 2200/451: the amplifier being a radio frequency amplifier - H03F 2200/537: A transformer being used as coupling element between two amplifying stages - H03F: AMPLIFIERS ## Abstract A power amplifier circuit includes: a high pass filter that has one end into which a high frequency input signal is inputted; a first amplifier that amplifies the high frequency input signal outputted from the other end of the high pass filter and outputs a high frequency signal obtained through the first amplification; a second amplifier that amplifies the high frequency signal and outputs a high frequency output signal obtained through the second amplification; an automatic transformer that performs impedance matching between the first amplifier and the second amplifier; and an impedance circuit, one end of which is electrically connected with the other end of the high pass filter, the other end of which is electrically connected with an output terminal of a bias circuit outputting bias voltage or bias current to the first amplifier, and that outputs the high frequency input signal to the bias circuit. ## Claims ### Claim 1 A power amplifier circuit comprising: a high pass filter into which a high frequency input signal is inputted at a first end; a first amplifier configured to amplify the high frequency input signal and to output a first amplified high frequency signal, the high frequency input signal being outputted from a second end of the high pass filter; a second amplifier configured to amplify the first amplified high frequency signal and to output a second amplified high frequency output signal; an automatic transformer that is electrically connected between the first amplifier and the second amplifier, and that is configured to perform impedance matching between the first amplifier and the second amplifier; and an impedance circuit having a first end electrically connected to the second end of the high pass filter, and a second end electrically connected to an output terminal of a bias circuit, wherein the bias circuit is configured to output a bias voltage or a bias current to the first amplifier, and wherein the impedance circuit is configured to supply the high frequency input signal from the second end of the high pass filter to the output terminal of the bias circuit. ### Claim 2 A power amplifier circuit comprising: a high pass filter into which a high frequency input signal is inputted at a first end; a first amplifier configured to amplify the high frequency input signal and to output a first amplified high frequency signal, the high frequency input signal being outputted from a second end of the high pass filter; a second amplifier configured to amplify the first amplified high frequency signal and to output a second amplified high frequency; a transmission line transformer that is electrically connected between the first amplifier and the second amplifier, and that is configured to perform impedance matching between the first amplifier and the second amplifier; and an impedance circuit having a first end electrically connected to the second end of the high pass filter, and a second end electrically connected to an output terminal of a bias circuit, wherein the bias circuit is configured to output a bias voltage or a bias current to the first amplifier, and wherein the impedance circuit is configured to supply the high frequency input signal from the second end of the high pass filter to the output terminal of the bias circuit. ### Claim 3 A power amplifier circuit comprising: a high pass filter into which a high frequency input signal is inputted at a first end; a first amplifier configured to amplify the high frequency input signal and to output a first amplified high frequency signal, the high frequency input signal being outputted from a second end of the high pass filter; a second amplifier configured to amplify the first amplified high frequency signal and to output a second amplified high frequency output signal; a conventional transformer that is electrically connected between the first amplifier and the second amplifier, and that is configured to perform impedance matching between the first amplifier and the second amplifier; and an impedance circuit having a first end electrically connected to the second end of the high pass filter, and a second end electrically connected to an output terminal of a bias circuit, wherein the bias circuit is configured to output a bias voltage or a bias current to the first amplifier, wherein the impedance circuit is configured to supply the high frequency input signal from the second end of the high pass filter to the output terminal of the bias circuit, and wherein the second end of the impedance circuit is electrically connected to an emitter of a transistor, and wherein the transistor is in the bias circuit, is emitter-follower connected, and is configured to output the bias voltage or the bias current from the emitter. ### Claim 4 (depends on 1) The power amplifier circuit according to claim 1, wherein the first amplifier comprises a plurality of cells that each comprise a unit transistor, each of the unit transistors being configured to amplify the high frequency input signal and to output an amplified high frequency signal, and wherein the impedance circuit comprises a plurality of unit impedance circuits, each of the plurality of cells further comprising a respective one of the plurality of unit impedance circuits. ### Claim 5 (depends on 2) The power amplifier circuit according to claim 2, wherein the first amplifier comprises a plurality of cells that each comprise a unit transistor, each of the unit transistors being configured to amplify the high frequency input signal and to output an amplified high frequency signal, and wherein the impedance circuit comprises a plurality of unit impedance circuits, each of the plurality of cells further comprising a respective one of the plurality of unit impedance circuits. ### Claim 6 (depends on 3) The power amplifier circuit according to claim 3, wherein the first amplifier comprises a plurality of cells that each comprise a unit transistor, each of the unit transistors being configured to amplify the high frequency input signal and to output an amplified high frequency signal, and wherein the impedance circuit comprises a plurality of unit impedance circuits, each of the plurality of cells further comprising a respective one of the plurality of unit impedance circuits. ### Claim 7 (depends on 1) The power amplifier circuit according to claim 1, wherein the impedance circuit comprises a capacitor. ### Claim 8 (depends on 2) The power amplifier circuit according to claim 2, wherein the impedance circuit comprises a capacitor. ### Claim 9 (depends on 3) The power amplifier circuit according to claim 3, wherein the impedance circuit comprises a capacitor. ### Claim 10 (depends on 1) The power amplifier circuit according to claim 1, wherein the impedance circuit comprises a capacitor and an inductor connected in series with each other. ### Claim 11 (depends on 2) The power amplifier circuit according to claim 2, wherein the impedance circuit comprises a capacitor and an inductor connected in series with each other. ### Claim 12 (depends on 3) The power amplifier circuit according to claim 3, wherein the impedance circuit comprises a capacitor and an inductor connected in series with each other. ### Claim 13 (depends on 1) The power amplifier circuit according to claim 1, wherein the second end of the impedance circuit is electrically connected to an emitter of a transistor, and wherein the transistor is in the bias circuit, is emitter-follower connected, and is configured to output the bias voltage or the bias current from the emitter. ### Claim 14 (depends on 2) The power amplifier circuit according to claim 2, wherein the second end of the impedance circuit is electrically connected to an emitter of a transistor, and wherein the transistor is in the bias circuit, is emitter-follower connected, and is configured to output the bias voltage or the bias current from the emitter.