# US 12,119,796 B2 · Radio-frequency power amplifier with intermodulation distortion mitigation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,119,796 B2 - Document ID: US12119796B2 - Status: Granted - Kind: B2 - Application number: 17/539,977 - Filed: 2021-12-01 - Published: 2023-06-01 - Granted: 2024-10-15 - Earliest claimed: 2021-12-01 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Nitesh Singhal - Web page: https://patentgrep.com/patent/US12119796B2 ## CPC - H03F 3/195: in integrated circuits - H03F 3/245: {with semiconductor devices only} - H03F 1/0266: {by using a signal derived from the input signal} - H03F 1/223: {with MOSFET's} - H03F 1/3205: {in field-effect transistor amplifiers} - H03F 1/3211: {in differential amplifiers} - H03F 1/3223: {using feed-forward (H03F1/3211 takes precedence)} - H03F 3/213: in integrated circuits - H03F 3/45179: {using MOSFET transistors as the active amplifying circuit (H03F3/45278 takes precedence)} - H04B 1/40: Circuits - H03F 2200/06: A balun, i.e. balanced to or from unbalanced converter, being present at the input of an amplifier - H03F 2200/451: the amplifier being a radio frequency amplifier - H03F 2200/456: A scaled replica of a transistor being present in an amplifier - H03F 2200/534: Transformer coupled at the input of an amplifier - H03F: AMPLIFIERS - H04B: TRANSMISSION ## Abstract An electronic device may include wireless circuitry with a processor, a transceiver, an antenna, and a front-end module coupled between the transceiver and the antenna. The front-end module may include one or more power amplifiers for amplifying a signal for transmission through the antenna. Radio-frequency power amplifier circuitry may include an amplifier, an input transformer for coupling radio-frequency input signals to the amplifier, an active inductor load coupled to the input transformer, and a second order intermodulation generation circuit configured to generate and inject a second order intermodulation product into the input transformer. The injected second order intermodulation product can be used to cancel out unwanted third order intermodulation products generated by the amplifier, which reduces intermodulation distortion experienced by the amplifier circuitry. ## Claims ### Claim 1 Radio-frequency power amplifier circuitry comprising: a first input transistor having a first source-drain terminal coupled to a ground power supply line, a second source-drain terminal coupled to a first amplifier output terminal, and a gate terminal; a second input transistor having a first source-drain terminal coupled to the ground power supply line, a second source-drain terminal coupled to a second amplifier output terminal, and a gate terminal; an input transformer configured to receive a radio-frequency signal and coupled to the gate terminals of the first and second input transistors; and a second order intermodulation generation circuit having an output coupled to the input transformer. ### Claim 2 (depends on 1) The radio-frequency power amplifier circuitry of claim 1, wherein the input transformer comprises: a primary inductor having first and second terminals configured to receive the radio-frequency signal; and a secondary inductor having a first terminal coupled to the gate terminal of the first input transistor and having a second terminal coupled to the gate terminal of the second input transistor. ### Claim 3 (depends on 2) The radio-frequency power amplifier circuitry of claim 2, further comprising: a first cascode transistor having a first source-drain terminal coupled to the second source-drain terminal of the first input transistor, a second source-drain terminal coupled to the first amplifier output terminal, and a gate terminal configured to receive a cascode bias voltage; and a second cascode transistor having a first source-drain terminal coupled to the second source-drain terminal of the second input transistor, a second source-drain terminal coupled to the second amplifier output terminal, and a gate terminal configured to receive the cascode bias voltage. ### Claim 4 (depends on 2) The radio-frequency power amplifier circuitry of claim 2, further comprising: an active inductor load circuit coupled to a center tap of the secondary inductor. ### Claim 5 (depends on 4) The radio-frequency power amplifier circuitry of claim 4, wherein the active inductor load circuit comprises: a load transistor having a first source-drain terminal coupled to the center tap of the secondary inductor, a second source-drain terminal coupled to the ground power supply line, and a gate terminal; a resistor having a first terminal coupled to the first source-drain terminal of the load transistor and having a second terminal coupled to the gate terminal of the load transistor; and a capacitor having a first terminal coupled to the gate terminal of the load transistor and having a second terminal coupled to the ground power supply line. ### Claim 6 (depends on 2) The radio-frequency power amplifier circuitry of claim 2, wherein the second order intermodulation generation circuit comprises: a first n-type transistor having a first source-drain terminal coupled to the gate terminal of the first input transistor, a second source-drain terminal coupled to a positive power supply line, and a gate terminal configured to receive a bias voltage/. ### Claim 7 (depends on 6) The radio-frequency power amplifier circuitry of claim 6, wherein the second order intermodulation generation circuit further comprises: a second n-type transistor having a first source-drain terminal coupled to the gate terminal of the second input transistor, a second source-drain terminal coupled to the positive power supply line, and a gate terminal configured to receive the bias voltage. ### Claim 8 (depends on 2) The radio-frequency power amplifier circuitry of claim 2, wherein the second order intermodulation generation circuit comprises: a first p-type transistor having a first source-drain terminal coupled to a center tap of the secondary inductor, a second source-drain terminal coupled to a positive power supply line, and a gate terminal configured to receive a bias voltage via a first bias resistor; and a second p-type transistor having a first source-drain terminal coupled to the center tap of the secondary inductor, a second source-drain terminal coupled to the positive power supply line, and a gate terminal configured to receive the bias voltage via a second bias resistor. ### Claim 9 (depends on 8) The radio-frequency power amplifier circuitry of claim 8, wherein the second order intermodulation generation circuit further comprises: a first capacitor having a first terminal coupled to the gate terminal of the first p-type transistor and having a second terminal coupled to the first terminal of the primary inductor; and a second capacitor having a first terminal coupled to the gate terminal of the second p-type transistor and having a second terminal coupled to the second terminal of the primary inductor. ### Claim 10 (depends on 8) The radio-frequency power amplifier circuitry of claim 8, further comprising: a bias voltage generation circuit that includes a bias diode, an operational amplifier configured to receive a voltage from the bias diode and to output the bias voltage, a first additional transistor having a gate terminal configured to receive the bias voltage from the operational amplifier, a second additional transistor coupled in series with the first additional transistor, a resistor having a first terminal coupled to a first source-drain terminal of the second additional transistor and having a second terminal coupled to the gate terminal of the second additional transistor, and a capacitor having a first terminal coupled to the gate terminal of the second additional transistor and having a second terminal coupled to the ground power supply line. ### Claim 11 A method of operating wireless circuitry, comprising: receiving a radio-frequency signal at an input transformer; receiving, at an amplifier, the radio-frequency signal from the input transformer; generating a second order intermodulation signal using a second order intermodulation generation circuit and coupling the second order intermodulation signal to the input transformer; and combining the second order intermodulation signal with the radio-frequency signal to generate corresponding signals that cancel out third order intermodulation signals associated with the amplifier. ### Claim 12 (depends on 11) The method of claim 11, further comprising: converting the second order intermodulation signal from a current signal to a voltage signal using an active inductor load circuit coupled to the input transformer. ### Claim 13 (depends on 11) The method of claim 11, wherein the amplifier includes first and second input transistors, and wherein generating the second order intermodulation signal comprises: using a first n-type transistor having a source terminal coupled to a gate terminal of the first input transistor to output a second order intermodulation current through a secondary inductor in the input transformer; and using a second n-type transistor having a source terminal coupled to a gate terminal of the second input transistor to output the second order intermodulation current through the secondary inductor in the input transformer. ### Claim 14 (depends on 13) The method of claim 13, further comprising: providing a bias voltage to gate terminals of the first and second n-type transistors. ### Claim 15 (depends on 11) The method of claim 11, wherein the input transformer includes a primary inductor configured to receive the radio-frequency signal and includes a secondary inductor, and wherein generating the second order intermodulation signal comprises: using a first p-type transistor to output a second order intermodulation current to a center tap of the secondary inductor; and using a second p-type transistor to output the second order intermodulation current to the center tap of the secondary inductor. ### Claim 16 (depends on 15) The method of claim 15, further comprising: coupling a first terminal of the primary inductor to a gate terminal of the first p-type transistor via a first capacitor; and coupling a second terminal of the primary inductor to a gate terminal of the second p-type transistor via a second capacitor. ### Claim 17 An electronic device comprising: one or more processors configured to generate transmit signals; a transceiver configured to generate radio-frequency signals based on the transmit signals; and power amplifier circuitry configured to amplify the radio-frequency signals for wireless transmission by an antenna, the power amplifier circuitry having a first input transistor having a source terminal coupled to a ground power supply line, a drain terminal coupled to a first amplifier output terminal, and a gate terminal, a second input transistor having a source terminal coupled to the ground power supply line, a drain terminal coupled to a second amplifier output terminal, and a gate terminal, an input transformer configured to receive the radio-frequency signals and coupled to the gate terminals of the first and second input transistors, and a second order intermodulation generation circuit coupled to the input transformer and configured to generate second order intermodulation signals that are used to generate third order intermodulation cancelling signals. ### Claim 18 (depends on 17) The electronic device of claim 17, wherein the input transformer comprises: a primary coil having first and second terminals configured to receive the radio-frequency signals; and a secondary coil having a first terminal coupled to the gate terminal of the first input transistor and having a second terminal coupled to the gate terminal of the second input transistor. ### Claim 19 (depends on 18) The electronic device of claim 18, wherein the second order intermodulation generation circuit comprises: a first n-type transistor having a source terminal coupled to the gate terminal of the first input transistor, a drain terminal coupled to a positive power supply line, and a gate terminal configured to receive a bias voltage; and a second n-type transistor having a source terminal coupled to the gate terminal of the second input transistor, a drain terminal coupled to the positive power supply line, and a gate terminal configured to receive the bias voltage. ### Claim 20 (depends on 18) The electronic device of claim 18, wherein the second order intermodulation generation circuit comprises: a first p-type transistor having a drain terminal coupled to a center tap of the secondary coil, a source terminal coupled to a positive power supply line, and a gate terminal configured to receive a bias voltage; and a second p-type transistor having a drain terminal coupled to the center tap of the secondary coil, a source terminal coupled to the positive power supply line, and a gate terminal configured to receive the bias voltage.