# US 2013/0154729 A1 · Dynamic loadline power amplifier with baseband linearization > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0154729 A1 - Document ID: US20130154729A1 - Status: Published application - Kind: A1 - Application number: 13/714,600 - Filed: 2012-12-14 - Published: 2013-06-20 - Earliest claimed: 2011-12-16 - Assignees: RF Micro Devices, Inc. - Inventors: Andrew F. Folkmann; Ramon Antonio Beltran Lizarraga - Web page: https://patentgrep.com/patent/US20130154729A1 ## CPC - H03G 3/20: Automatic control ({H03G3/005 takes precedence;} combined with volume compression or expansion H03G7/00) - H03F 1/0288: {using a main and one or several auxiliary peaking amplifiers whereby the load is connected to the main amplifier using an impedance inverter, e.g. Doherty amplifiers} - H03F 3/189: High-frequency amplifiers, e.g. radio frequency amplifiers - H03F 3/68: Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics {(power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602)} - H03F 3/72: Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal - H03G 3/3042: {in modulators, frequency-changers, transmitters or power amplifiers} - H03G: CONTROL OF AMPLIFICATION - H03F: AMPLIFIERS ## Abstract Radio frequency (RF) amplification devices and methods of amplifying RF signals are disclosed. In one embodiment, an RF amplification device includes a control circuit and a Doherty amplifier configured to amplify an RF signal. The Doherty amplifier includes a main RF amplification circuit and a peaking RF amplification circuit. The control circuit is configured to activate the peaking RF amplification circuit in response to the RF signal reaching a threshold level. In this manner, the activation of the peaking RF amplification circuit can be precisely controlled. ## Claims ### Claim 1 A radio frequency (RF) amplification device comprising: a Doherty amplifier configured to amplify an RF signal, wherein the Doherty amplifier comprises a main RF amplification circuit and a peaking RF amplification circuit; and a control circuit configured to activate the peaking RF amplification circuit in response to a signal level of the RF signal reaching a threshold level. ### Claim 2 (depends on 1) The RF amplification device of claim 1 wherein: the peaking RF amplification circuit is operable to receive a control signal having a control signal level, wherein the peaking RF amplification circuit is configured to be activated in response to the control signal level being above an activation level; and the control circuit is further configured to: generate the control signal; and provide the control signal level above the activation level in response to the signal level of the RF signal reaching the threshold level so as to activate the peaking RF amplification circuit. ### Claim 3 (depends on 2) The RF amplification device of claim 2 wherein: the control circuit is further configured to generate the control signal as a gain control signal such that the control signal level is a gain control signal level; the peaking RF amplification circuit is configured to provide amplification in accordance with a peaking amplifier gain set based on the gain control signal level of the gain control signal; and wherein the main RF amplification circuit and the peaking RF amplification circuit are operably associated such that: while the main RF amplification circuit is activated and the peaking RF amplification circuit is deactivated, the main RF amplification circuit is configured to amplify the RF signal in accordance with a main amplifier gain; and while the main RF amplification circuit is activated and the peaking RF amplification circuit is activated, the RF signal is split into a first RF split signal and a second RF split signal that are quadrature phased with respect to one another, so that the main RF amplification circuit is configured to amplify the first RF split signal and the peaking RF amplification circuit is configured to amplify the second RF split signal. ### Claim 4 (depends on 3) The RF amplification device of claim 3 wherein: the control circuit is further configured to generate the control signal as the gain control signal such that the control signal level is the gain control signal level; and the peaking RF amplification circuit comprises: a driver amplifier stage operable to receive the second RF split signal and the gain control signal, the driver amplifier stage being configured to amplify the second RF split signal in accordance with a driver amplifier stage gain and to set the driver amplifier stage gain in accordance with the gain control signal level of the gain control signal; and a peaking amplifier stage coupled in cascade with the driver amplifier stage, the peaking amplifier stage being operable to receive the second RF split signal from the driver amplifier stage and being configured to amplify the second RF split signal in accordance with a peaking amplifier stage gain, wherein the peaking amplifier gain is a combination of the driver amplifier stage gain and the peaking amplifier stage gain. ### Claim 5 (depends on 4) The RF amplification device of claim 4 wherein the peaking amplifier gain is approximately equal to the driver amplifier stage gain magnified by the peaking amplifier stage gain. ### Claim 6 (depends on 3) The RF amplification device of claim 3 wherein: the control circuit is further configured to generate the control signal as the gain control signal such that the control signal level is the gain control signal level; and the peaking RF amplification circuit comprises a peaking amplifier stage operable to receive the second RF split signal and being configured to amplify the second RF split signal in accordance with a peaking amplifier stage gain, wherein the peaking amplifier stage gain is set in accordance with the gain control signal level. ### Claim 7 (depends on 6) The RF amplification device of claim 6 wherein the main RF amplification circuit is operable to receive a second gain control signal having a second gain control signal level, the main RF amplification circuit being configured to provide amplification in accordance with the main amplifier gain, and to set the main amplifier gain in accordance with the second gain control signal level. ### Claim 8 (depends on 7) The RF amplification device of claim 7 wherein the Doherty amplifier is configured to provide amplification in accordance to a Doherty amplifier gain and wherein the control circuit is configured to: generate the gain control signal; generate the second gain control signal; and provide the gain control signal level and the second gain control signal level such that the Doherty amplifier gain is substantially linearized while the main RF amplification circuit is activated and the peaking RF amplification circuit is activated. ### Claim 9 (depends on 1) The RF amplification device of claim 1 wherein the main RF amplification circuit and the peaking RF amplification circuit are operably associated such that: while the main RF amplification circuit is activated and the peaking RF amplification circuit is deactivated, the main RF amplification circuit is configured to amplify the RF signal in accordance with a main amplifier gain; and while the main RF amplification circuit is activated and the peaking RF amplification circuit is deactivated, the RF signal is split into a first RF split signal and a second RF split signal that are quadrature phased with respect to one another, so that the main RF amplification circuit is configured to amplify the first RF split signal and the peaking RF amplification circuit is configured to amplify the second RF split signal. ### Claim 10 (depends on 9) The RF amplification device of claim 9 wherein the main RF amplification circuit and the peaking RF amplification circuit are further operably associated such that the first RF split signal and the second RF split signal are phase-aligned and combined to output the RF signal from the Doherty amplifier after amplification. ### Claim 11 (depends on 9) The RF amplification device of claim 9 further comprising a hybrid coupler wherein: the main RF amplification circuit comprises a main amplifier stage and a first phase-shifting transmission line element, wherein: the main amplifier stage has a first input terminus and a first output terminus and is configured to provide amplification in accordance with the main amplifier gain; and the first phase-shifting transmission line element is coupled to the first output terminus and is configured to provide a quadrature phase shift; the peaking RF amplification circuit comprises a peaking amplifier stage and a second phase-shifting transmission line element, wherein: the peaking amplifier stage has a second input terminus and a second output terminus and is configured to provide amplification in accordance with a peaking amplifier stage gain; and the second phase-shifting transmission line element is coupled to the second output terminus and is configured to provide a quadrature phase shift; and the hybrid coupler is operable to receive the RF signal and is coupled to the first input terminus and the second input terminus, wherein the hybrid coupler is configured to transmit the RF signal to the main amplifier stage while the main RF amplification circuit is activated and the peaking RF amplification circuit is deactivated, and the hybrid coupler is configured to split the RF signal into the first RF split signal and the second RF split signal to transmit the first RF split signal to the first input terminus and to transmit the second RF split signal to the second input terminus while the main RF amplification circuit is activated and the peaking RF amplification circuit is activated. ### Claim 12 (depends on 9) The RF amplification device of claim 9 wherein the peaking RF amplification circuit comprises a peaking amplifier stage and a phase-shifting transmission line element and wherein: the peaking amplifier stage has an input terminus and is configured to provide amplification in accordance with a peaking amplifier stage gain; and the phase-shifting transmission line element is coupled to the input terminus and is configured to provide a quadrature phase shift such that the RF signal is split into the first RF split signal and the second RF split signal while the main RF amplification circuit is activated and the peaking RF amplification circuit is activated. ### Claim 13 (depends on 9) The RF amplification device of claim 9 wherein: the main RF amplification circuit is operable to receive a gain control signal having a gain control signal level, wherein the main RF amplification circuit is configured to provide amplification in accordance with the main amplifier gain and to set the main amplifier gain in accordance with a gain control signal level of a gain control signal; and the peaking RF amplification circuit is operable to receive a second gain control signal having a second gain control signal level, wherein the peaking RF amplification circuit is configured to provide amplification in accordance with a peaking amplifier gain and to set the peaking amplifier gain in accordance with the second gain control signal level. ### Claim 14 (depends on 13) The RF amplification device of claim 13 wherein the Doherty amplifier is configured to provide amplification in accordance with a Doherty amplifier gain and wherein the control circuit is configured to: generate the gain control signal; generate the second gain control signal; and provide the gain control signal level and the second gain control signal level such that the Doherty amplifier gain is substantially linearized while the main RF amplification circuit is activated and the peaking RF amplification circuit is deactivated. ### Claim 15 (depends on 1) The RF amplification device of claim 1 wherein the control circuit is further configured to: receive an instantaneous power indication signal having an instantaneous power indication signal level indicative of the signal level of the RF signal, wherein the signal level reaches the threshold level when the instantaneous power indication signal level reaches a power threshold level; generate a gain control signal having a gain control signal level; and provide the gain control signal level above an activation level so as to activate the peaking RF amplification circuit in response to the instantaneous power indication signal level reaching the power threshold level. ### Claim 16 (depends on 15) The RF amplification device of claim 15 wherein: the Doherty amplifier is configured to provide amplification in accordance to a Doherty amplifier gain; the peaking RF amplification circuit is configured to provide amplification in accordance with a peaking amplifier gain set based on the gain control signal level of the gain control signal; and the control circuit is further configured to provide the gain control signal level and set the peaking amplifier gain such that the Doherty amplifier gain is linearized. ### Claim 17 (depends on 16) The RF amplification device of claim 16 wherein: the peaking RF amplification circuit is configured to provide amplification in accordance with the peaking amplifier gain set based on the gain control signal level of the gain control signal; and the control circuit is further configured to provide the gain control signal level as a function of the instantaneous power indication signal level. ### Claim 18 (depends on 15) The RF amplification device of claim 15 wherein: the peaking RF amplification circuit is configured to provide amplification in accordance with a peaking amplifier gain set based on the gain control signal level of the gain control signal; and the control circuit is further configured to provide the gain control signal level as a function of the instantaneous power indication signal level. ### Claim 19 (depends on 1) The RF amplification device of claim 1 wherein the peaking RF amplification circuit is configured to have an AB amplifier topology. ### Claim 20 (depends on 19) The RF amplification device of claim 19 wherein the main RF amplification circuit is configured to have an AB amplifier topology. ### Claim 21 A method of amplifying an RF signal comprising: activating a main RF amplification circuit in a Doherty amplifier so that the main RF amplification circuit amplifies the RF signal while a peaking RF amplification circuit in the Doherty amplifier is deactivated; detecting a signal level of the RF signal; and activating the peaking RF amplification circuit in response to the signal level of the RF signal reaching a threshold level.