# US 11,444,590 B2 · Class-G control system with low latency signal path > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,590 B2 - Document ID: US11444590B2 - Status: Granted - Kind: B2 - Application number: 17/118,411 - Filed: 2020-12-10 - Published: 2021-06-17 - Granted: 2022-09-13 - Earliest claimed: 2019-12-16 - Assignees: Synaptics Incorporated - Applicants: Synaptics Incorporated - Inventors: Dan Shen; Lorenzo Crespi - Web page: https://patentgrep.com/patent/US11444590B2 ## CPC - H03F 3/2175: {using analogue-digital or digital-analogue conversion (H03F3/2173 takes precedence)} - G10K 11/17855: {for improving speed or power requirements} - G10K 11/1787: {General system configurations} - H03F 1/0227: {using supply converters} - H03F 3/181: Low-frequency amplifiers, e.g. audio preamplifiers - H04R 3/00: Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) - G10K 2210/1081: Earphones, e.g. for telephones, ear protectors or headsets - G10K 2210/3016: Control strategies, e.g. energy minimization or intensity measurements - G10K 2210/3056: Variable gain - H03F 2200/03: the amplifier being designed for audio applications - H03F 2200/102: A non-specified detector of a signal envelope being used in an amplifying circuit - H03F: AMPLIFIERS - G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract Systems and methods include a digital control module that receives and processes audio data for output through a loudspeaker. An analog block receives the audio data and the power control signal and amplifies the audio data for output. A first processing path includes a buffer to delay the audio data, a first component to combine the buffered audio data and anti-noise. A second processing path includes an absolute value block to receive the audio data and an envelope detector to receive the absolute value data and generate a maximum value for the envelope. An anti-noise path includes an absolute value block configured to determine an anti-noise absolute value which is combined with the absolute value anti-noise data. A power generator receives the output from the envelope detector and updates a power level to approximate a minimum powered needed to process the audio signal. ## Claims ### Claim 1 A method comprising: processing an audio input signal on a first processing path comprising: buffering the audio input signal; combining the buffered audio input signal with a second channel of audio data in a low-latency path to produce a first combined audio output signal; and providing the first combined audio output signal to an audio output driver; and processing the audio input signal on a second processing path comprising: determining an absolute value of the audio input signal; combining the absolute value of the audio input signal with an absolute value of the second channel of audio data in a mix to generate a second combined audio output signal; determining an envelope for the second combined audio output signal; and adjusting a power supplied to the audio driver based on the determined envelope. ### Claim 2 (depends on 1) The method of claim 1, wherein the audio input signal is a digital audio stream for playback on a loudspeaker. ### Claim 3 (depends on 1) The method of claim 1, wherein the second channel of audio data comprises noise cancellation data and wherein the method further comprises generating a noise cancellation signal from the noise cancellation data to cancel detected ambient noise. ### Claim 4 (depends on 1) The method of claim 1, wherein buffering the audio input signal comprises delaying the processing of the audio input signal in the first processing path such that the power supplied to the audio driver from the second processing path and the audio signal supplied to the audio driver from the first processing path are received by the audio driver at approximately the same time. ### Claim 5 (depends on 1) The method of claim 1, further comprising determining an absolute value of the second channel of audio data. ### Claim 6 (depends on 1) The method of claim 1, further comprising predicting a maximum value of the second channel of audio data. ### Claim 7 (depends on 6) The method of claim 6, wherein the maximum value of the second channel of audio data is calculated, based at least in part, on a slope of the second channel of audio data over time. ### Claim 8 (depends on 1) The method of claim 1, further comprising processing the first combined audio output signal to drive a loudspeaker. ### Claim 9 (depends on 8) The method of claim 8, wherein processing the first combined audio output signal comprises converting the first combined audio output signal from digital to analog. ### Claim 10 (depends on 9) The method of claim 9, wherein processing the first combined audio output signal comprises passing the analog signal through a class AB amplifier or a class D amplifier. ### Claim 11 A system comprising: a digital control module configured to receive and process audio data on a first processing path to generate audio output and process the audio data on a second processing path to generate a power control signal based on a predicted amplitude of the generated audio output, wherein the second processing path includes: an absolute value block configured to receive the audio data and output an audio signal absolute value; and an envelope detector configured to receive the audio signal absolute value and generate a maximum value for an envelope; and an analog block configured to receive the audio output and the power control signal and amplify, based at least in part on the power control signal, the audio output for playback on a loudspeaker. ### Claim 12 (depends on 11) The system of claim 11, wherein the first processing path comprises a buffer configured to receive and delay the audio data and output buffered audio data. ### Claim 13 (depends on 12) The system of claim 12, wherein the first processing path further comprises: a first component configured to receive the buffered audio data and a second channel of data and combine the buffered audio data and the second channel of data for output to the audio analog block. ### Claim 14 (depends on 11) The system of claim 11, further comprising a third processing path configured to process a second channel of data comprising an absolute value block configured to determine an absolute value of the second channel of data; and wherein the second processing path further comprises a second component configured to combine the absolute value of the second channel of data and the audio signal absolute value prior to input to the envelope detector with a mix that may differ from an actual output signal. ### Claim 15 (depends on 11) The system of claim 11, further comprising a power generator configured to receive the output from the envelope detector and update a power level to approximate a maximum power required to process the audio signal. ### Claim 16 (depends on 11) The system of claim 11, wherein the received audio signal is buffered and delayed before output and the power control signal is generated without a delay. ### Claim 17 (depends on 11) The system of claim 11, wherein the digital control module further comprises a maximum value block configured to receive a second channel of data and generate a predicted maximum value; and wherein the predicted maximum value is generated based on a slope of the second channel of data. ### Claim 18 (depends on 11) The system of claim 11, wherein the analog block comprises: a digital to analog converter configured to receive the audio data and output an analog representation of the audio data; an amplifier configured to receive and amplify the analog representation of the analog data; and a loudspeaker configured to receive the amplified analog representation and generate a sound for a user. ### Claim 19 (depends on 11) The system of claim 11, wherein the digital control module is further configured to receive and process a second channel of data in a low latency data path; and wherein the predicted amplitude of the output signal is based on a slope of the second channel of data.