# US 12,119,794 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 12,119,794 B2 - Document ID: US12119794B2 - Status: Granted - Kind: B2 - Application number: 17/470,115 - Filed: 2021-09-09 - Published: 2021-12-30 - Granted: 2024-10-15 - Earliest claimed: 2020-04-28 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Shingo Yanagihara - Web page: https://patentgrep.com/patent/US12119794B2 ## CPC - H03F 3/211: {using a combination of several amplifiers (H03F3/60 takes precedence)} - H03F 1/02: Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation - H03F 1/223: {with MOSFET's} - H03F 3/195: in integrated circuits - H03F 2200/09: A balun, i.e. balanced to or from unbalanced converter, being present at the output of an amplifier - H03F 2200/451: the amplifier being a radio frequency amplifier - H03F 2200/534: Transformer coupled at the input of an amplifier - H03F 2200/537: A transformer being used as coupling element between two amplifying stages - H03F 2200/541: Transformer coupled at the output of an amplifier - H03F: AMPLIFIERS ## Abstract A power amplifier circuit includes a first power amplifier, a balun, a second power amplifier, and a third power amplifier. The second and third power amplifiers each include unit bipolar transistors each including a first terminal electrically connected to a reference potential, a second terminal, and a third terminal that outputs an amplified signal; a common input terminal electrically connected to the second terminals of the transistors and receives an RF signal; a common bias terminal electrically connected to the second terminals of the transistors and receives a bias current; a common output terminal electrically connected to the third terminals of the transistors and outputs the amplified signal; and resistance elements each of which is electrically connected between the common input terminal and the second terminal of a corresponding one of the transistors and cuts a DC component of the bias current. ## Claims ### Claim 1 A power amplifier circuit comprising: a first power amplifier in or on a first chip; a balun comprising a primary winding and a secondary winding, the primary winding having a first end connected to the first power amplifier and a second end electrically connected to a reference potential; a second power amplifier in or on a second chip and electrically connected to a first end of the secondary winding of the balun; and a third power amplifier in or on the second chip and electrically connected to a second end of the secondary winding of the balun, wherein: the first power amplifier comprises a plurality of field-effect transistors that are stack-connected, and the second power amplifier and the third power amplifier each comprise: a plurality of unit bipolar transistors each including a first terminal that is electrically connected to the reference potential, a second terminal that is configured to receive a radio-frequency signal and a bias current, and a third terminal that is configured to output an amplified signal obtained by amplifying the radio-frequency signal, a common input terminal that is electrically connected in parallel to the second terminals of the plurality of unit bipolar transistors, and that is configured to receive the radio-frequency signal, a common bias terminal that is electrically connected in parallel to the second terminals of the plurality of unit bipolar transistors, and that is configured to receive the bias current, a common output terminal that is electrically connected in parallel to the third terminals of the plurality of unit bipolar transistors, and that is configured to output the amplified signal, and a plurality of resistance elements each being electrically connected between the common input terminal and the second terminal of a corresponding one of the plurality of unit bipolar transistors, and each being configured to limit a direct current component of the bias current. ### Claim 2 (depends on 1) The power amplifier circuit according to claim 1, wherein the first chip is a silicon on insulator (SOI) chip or a complementary metal oxide semiconductor (CMOS) chip, and the second chip is a gallium arsenide (GaAs) chip, a gallium nitride (GaN) chip, an indium phosphide (InP) chip, or a silicon germanium (SiGe) chip. ### Claim 3 (depends on 1) The power amplifier circuit according to claim 1, wherein the balun is in or on the first chip. ### Claim 4 (depends on 2) The power amplifier circuit according to claim 2, wherein the balun is in or on the first chip. ### Claim 5 (depends on 1) The power amplifier circuit according to claim 1, further comprising: a first bias circuit configured to output the bias current to the second power amplifier and to the third power amplifier, wherein the first bias circuit comprises: a first transistor including a first terminal, a second terminal, and a third terminal, the first terminal being electrically connected to the reference potential, a second transistor including a first terminal, a second terminal, and a third terminal, the first terminal of the second transistor being electrically connected to the second terminal and the third terminal of the first transistor, the second terminal of the second transistor being electrically connected to the third terminal of the second transistor, and the third terminal of the second transistor being configured to receive a control current, a third transistor including a first terminal, a second terminal, and a third terminal, the first terminal of the third transistor being electrically connected to the reference potential, and a fourth transistor including a first terminal, a second terminal, and a third terminal, the first terminal of the fourth transistor being electrically connected to the second terminal and the third terminal of the third transistor, the second terminal of the fourth transistor being electrically connected to the third terminal of the second transistor, the third terminal of the fourth transistor being configured to receive a power supply voltage, and the first terminal of the fourth transistor being configured to output the bias current. ### Claim 6 (depends on 2) The power amplifier circuit according to claim 2, further comprising: a first bias circuit configured to output the bias current to the second power amplifier and to the third power amplifier, wherein the first bias circuit comprises: a first transistor including a first terminal, a second terminal, and a third terminal, the first terminal being electrically connected to the reference potential, a second transistor including a first terminal, a second terminal, and a third terminal, the first terminal of the second transistor being electrically connected to the second terminal and the third terminal of the first transistor, the second terminal of the second transistor being electrically connected to the third terminal of the second transistor, and the third terminal of the second transistor being configured to receive a control current, a third transistor including a first terminal, a second terminal, and a third terminal, the first terminal of the third transistor being electrically connected to the reference potential, and a fourth transistor including a first terminal, a second terminal, and a third terminal, the first terminal of the fourth transistor being electrically connected to the second terminal and the third terminal of the third transistor, the second terminal of the fourth transistor being electrically connected to the third terminal of the second transistor, the third terminal of the fourth transistor being configured to receive a power supply voltage, and the first terminal of the fourth transistor being configured to output the bias current. ### Claim 7 (depends on 3) The power amplifier circuit according to claim 3, further comprising: a first bias circuit configured to output the bias current to the second power amplifier and to the third power amplifier, wherein the first bias circuit comprises: a first transistor including a first terminal, a second terminal, and a third terminal, the first terminal being electrically connected to the reference potential, a second transistor including a first terminal, a second terminal, and a third terminal, the first terminal of the second transistor being electrically connected to the second terminal and the third terminal of the first transistor, the second terminal of the second transistor being electrically connected to the third terminal of the second transistor, and the third terminal of the second transistor being configured to receive a control current, a third transistor including a first terminal, a second terminal, and a third terminal, the first terminal of the third transistor being electrically connected to the reference potential, and a fourth transistor including a first terminal, a second terminal, and a third terminal, the first terminal of the fourth transistor being electrically connected to the second terminal and the third terminal of the third transistor, the second terminal of the fourth transistor being electrically connected to the third terminal of the second transistor, the third terminal of the fourth transistor being configured to receive a power supply voltage, and the first terminal of the fourth transistor being configured to output the bias current. ### Claim 8 (depends on 5) The power amplifier circuit according to claim 5, wherein the first transistor is a bipolar transistor in or on the second chip. ### Claim 9 (depends on 1) The power amplifier circuit according to claim 1, further comprising: a second bias circuit configured to output a bias voltage to the second terminal of each of the plurality of field-effect transistors. ### Claim 10 (depends on 2) The power amplifier circuit according to claim 2, further comprising: a second bias circuit configured to output a bias voltage to the second terminal of each of the plurality of field-effect transistors. ### Claim 11 (depends on 3) The power amplifier circuit according to claim 3, further comprising: a second bias circuit configured to output a bias voltage to the second terminal of each of the plurality of field-effect transistors. ### Claim 12 (depends on 5) The power amplifier circuit according to claim 5, further comprising: a second bias circuit configured to output a bias voltage to the second terminal of each of the plurality of field-effect transistors. ### Claim 13 (depends on 8) The power amplifier circuit according to claim 8, further comprising: a second bias circuit configured to output a bias voltage to the second terminal of each of the plurality of field-effect transistors. ### Claim 14 (depends on 1) The power amplifier circuit according to claim 1, further comprising: a ramp control circuit configured to output a bias voltage to a second terminal of any one of the plurality of field-effect transistors, the bias voltage being based on a control voltage that changes in a ramped manner. ### Claim 15 (depends on 2) The power amplifier circuit according to claim 2, further comprising: a ramp control circuit configured to output a bias voltage to a second terminal of any one of the plurality of field-effect transistors, the bias voltage being based on a control voltage that changes in a ramped manner. ### Claim 16 (depends on 3) The power amplifier circuit according to claim 3, further comprising: a ramp control circuit configured to output a bias voltage to a second terminal of any one of the plurality of field-effect transistors, the bias voltage being based on a control voltage that changes in a ramped manner. ### Claim 17 (depends on 5) The power amplifier circuit according to claim 5, further comprising: a ramp control circuit configured to output a bias voltage to a second terminal of any one of the plurality of field-effect transistors, the bias voltage being based on a control voltage that changes in a ramped manner. ### Claim 18 (depends on 8) The power amplifier circuit according to claim 8, further comprising: a ramp control circuit configured to output a bias voltage to a second terminal of any one of the plurality of field-effect transistors, the bias voltage being based on a control voltage that changes in a ramped manner. ### Claim 19 (depends on 9) The power amplifier circuit according to claim 9, further comprising: a ramp control circuit configured to output a bias voltage to a second terminal of any one of the plurality of field-effect transistors, the bias voltage being based on a control voltage that changes in a ramped manner.