# US 9,520,907 B2 · Methods and apparatus for envelope tracking system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,907 B2 - Document ID: US9520907B2 - Status: Granted - Kind: B2 - Application number: 14/181,714 - Filed: 2014-02-16 - Published: 2015-08-20 - Granted: 2016-12-13 - Earliest claimed: 2014-02-16 - Assignees: Mediatek Inc. - Applicants: Mediatek Inc. - Inventors: Chia-Sheng Peng; Wei-Cheng Liu; Sheng-Hong Yan; Paul Cheng Po Liang - Web page: https://patentgrep.com/patent/US9520907B2 ## CPC - H04B 1/0475: {with means for limiting noise, interference or distortion (H04B1/0483 takes precedence)} - H03F 1/0227: {using supply converters} - H03F 1/3241: {using predistortion circuits (H03F1/3211, H03F1/3217 take precedence)} - H03F 1/56: Modifications of input or output impedances, not otherwise provided for - H03F 3/24: of transmitter output stages - H03F 3/245: {with semiconductor devices only} - H04B 1/0458: {Arrangements for matching and coupling between power amplifier and antenna or between amplifying stages (matching circuits in general H03H)} - H03F 2200/102: A non-specified detector of a signal envelope being used in an amplifying circuit - H04B 2001/0408: {with power amplifiers} - H04B 2001/0425: {with linearisation using predistortion} - H04B: TRANSMISSION - H03F: AMPLIFIERS ## Abstract A communication unit comprises a radio frequency, RF, transmitter comprising: a power amplifier, PA, module; an envelope tracking system operably coupled to the PA module and arranged to variably control a supply voltage for the PA module; and a load control system operably coupled to an output of the PA module and arranged to control a power amplifier output load. ## Claims ### Claim 1 A communication unit comprising a radio frequency, RF, transmitter comprising: a transmit path comprising: a digital predistortion, DPD, module arranged to receive and distort an input transmit signal; an RF transmit block arranged to receive the distorted transmit signal and to amplify and up-convert the distorted transmit signal and apply the amplified, up-converted distorted transmit signal to the PA module; and a power amplifier, PA, module; and an envelope tracking system comprising: an envelope detector arranged to detect an instantaneous envelope of the input transmit signal; an envelope to supply mapping component arranged to set a supply voltage level based on the detected envelope; and a supply modulator operably coupled to a supply of the PA module and arranged to variably control a supply voltage therefor; wherein the RF transmitter further comprises a power controller operably coupled and arranged to receive a transmit power outputted from the RF transmitter in order to set levels within each of: the DPD module, the RF transmit block, envelope to supply mapping component. ### Claim 2 (depends on 1) The communication unit of claim 1 further comprising a switchable transformer-based voltage combiner operably coupled to a plurality of power amplifiers, PAs, of the PA module such that an output power of the PA module is selectable by applying the amplified, up-converted distorted transmit signal concurrently to a number of the PAs. ### Claim 3 (depends on 2) The communication unit of claim 2 further comprising a combiner controller operably coupled to respective inputs of the plurality of PAs by respective switches and arranged to switch the amplified, up-converted distorted transmit signal to a number of the PAs according to an operating average output power for the combined PAs. ### Claim 4 (depends on 1) The communication unit of claim 1 further comprising a coupler operably coupled to an impedance detector and arranged to receive a portion of an output signal of the PA module and provide the output signal portion to the impedance detector that is arranged to provide a PA output impedance indication to the power controller, wherein the power controller sets levels within each of: the DPD module, the RF transmit block, envelope to supply mapping component based on the PA output impedance indication. ### Claim 5 (depends on 1) The communication unit of claim 1 further comprising an envelope to supply delay control module operably coupled to the envelope-to-supply matching component in the ET system whereby the envelope to supply delay control module adjusts a timing alignment between the envelope tracking path of the envelope tracking system and a transmit path of the RF transmitter to align the envelope tracking power amplifier module supply voltage to at least one instantaneous envelope of a waveform signal to be amplified. ### Claim 6 (depends on 1) The Communication unit of claim 1, where the RF transmitter is a portion of an integrated circuit. ### Claim 7 A communication unit comprising a radio frequency, RF, transmitter comprising: a digital predistortion, DPD, module arranged to receive and distort an input transmit signal, an RF transmit block arranged to receive the distorted transmit signal and to amplify and up-convert the distorted transmit signal and apply the amplified up-converted distorted transmit signal to the PA module; and a power amplifier, PA, module; an envelope tracking system comprising: an envelope detector arranged to detect an instantaneous envelope of the input transmit signal; an envelope to supply mapping component arranged to set a supply voltage level based on the detected envelope; and a supply modulator operably coupled to a supply of the PA module and arranged to variably control a supply voltage therefor; a switchable transformer-based voltage combiner operably coupled to a plurality of power amplifiers, PAs, of the PA module, wherein an output power of the PA module is selectable by applying the amplified, up-converted distorted transmit signal concurrently to a number of PAs; and a combiner controller operably coupled to respective inputs of the plurality of PAs by respective switches and arranged to switch the amplified, up-converted distorted transmit signal to a number of the PAs according to an operating arrange output power of the combined PAs; wherein the RF transmitter further comprises a power controller operably coupled and arranged to set levels within each of: the DPD module, the RF transmit block, the envelope to supply mapping component.