# US 12,191,824 B2 · Low voltage system for audio amplifiers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,824 B2 - Document ID: US12191824B2 - Status: Granted - Kind: B2 - Application number: 17/955,271 - Filed: 2022-09-28 - Published: 2023-04-13 - Granted: 2025-01-07 - Earliest claimed: 2021-09-29 - Assignees: Skyworks Solutions, Inc. - Applicants: Skyworks Solutions, Inc. - Inventors: Mark R. Peting; Taehwan Oh; Miles Reuben Thompson - Web page: https://patentgrep.com/patent/US12191824B2 ## CPC - H03F 3/217: Class D power amplifiers; Switching amplifiers - H03F 3/2173: {of the bridge type} - H02J 7/345: {using capacitors as storage or buffering devices} - H03F 3/183: with semiconductor devices only - H03F 3/2175: {using analogue-digital or digital-analogue conversion (H03F3/2173 takes precedence)} - H04R 1/1041: {Mechanical or electronic switches, or control elements (switches in general H01H)} - H04R 3/00: Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) - H03F 2200/03: the amplifier being designed for audio applications - H03F 2200/513: the amplifier being made for low supply voltages - H04R 2201/028: Structural combinations of loudspeakers with built-in power amplifiers, e.g. in the same acoustic enclosure (H04R2499/10 takes precedence; Single (sub)woofer with two or more satellite loudspeakers for mid- and high-frequency band reproduction driven via the (sub)woofer H04R2205/026) - H04R 2420/07: Applications of wireless loudspeakers or wireless microphones - H04R 2460/03: Aspects of the reduction of energy consumption in hearing devices - H03F: AMPLIFIERS - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - 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 In some embodiments, a low voltage system can include a capacitor between an output node of an amplifier and ground, with the output node connectable to a load, and the amplifier configured to operate with a series of pulses. The low voltage system can further include a monitoring circuit configured to monitor a voltage at the capacitor against a desired low voltage value, and a control system configured to generate the series of pulses for the amplifier, and to control charging and discharging of the capacitor based on an output of the monitoring circuit to regulate the voltage at the output node at approximately the desired low voltage value. ## Claims ### Claim 1 A low voltage system comprising: a capacitor between an output node of an amplifier and ground, the output node connectable to a load, the amplifier configured to operate with a series of pulses; a monitoring circuit configured to monitor a voltage at the capacitor against a desired low voltage value; a control system configured to generate the series of pulses for the amplifier, and to control charging and discharging of the capacitor based on an output of the monitoring circuit to regulate the voltage at the output node at approximately the desired low voltage value. ### Claim 2 (depends on 1) The low voltage system of claim 1 wherein the amplifier is an audio amplifier. ### Claim 3 (depends on 2) The low voltage system of claim 2 wherein the audio amplifier is a Class D audio amplifier. ### Claim 4 (depends on 1) The low voltage system of claim 1 wherein monitoring circuit includes a comparator configured to compare the voltage at the capacitor with the desired low voltage value and generate the output. ### Claim 5 (depends on 1) The low voltage system of claim 1 wherein the desired low voltage value is a reference voltage obtained from a reference source. ### Claim 6 (depends on 5) The low voltage system of claim 5 wherein the reference source is a programmable reference source configured to generate a plurality of reference values such that one of the reference values is the reference voltage approximately equal to the voltage at the capacitor. ### Claim 7 (depends on 1) The low voltage system of claim 1 wherein the control system is configured to control the amplifier by pulse-width modulation (PWM). ### Claim 8 (depends on 1) The low voltage system of claim 1 wherein the output node is connected to an output stage of the amplifier. ### Claim 9 (depends on 8) The low voltage system of claim 8 wherein the output stage includes a MOSFET circuit having first and second transistors arranged in series between a supply node and ground, such that the output node is at a node between the first and second transistors. ### Claim 10 (depends on 9) The low voltage system of claim 9 wherein the first transistor is a PMOS device and the second transistor is an NMOS device, such that a source of the first transistor is coupled to the supply node, a drain of the first transistor is coupled to a drain of the second transistor, and a source of the second transistor is coupled to the ground. ### Claim 11 A module comprising: a packaging substrate; and an audio amplification system implemented on the packaging substrate, the audio amplification including an output stage operable with a series of pulses, the output stage having an output node; and a low voltage system including a capacitor between the output node of the amplification stage and ground, the output node connectable to a load, the low voltage system further including a monitoring circuit configured to monitor a voltage at the capacitor against a desired low voltage value, low voltage system further including a control system configured to control charging and discharging of the capacitor based on an output of the monitoring circuit to regulate the voltage at the output node at approximately the desired low voltage value. ### Claim 12 (depends on 11) The module of claim 11 wherein the output stage of the audio amplification system is implemented on a die. ### Claim 13 (depends on 12) The module of claim 12 wherein the capacitor is implemented outside of the die. ### Claim 14 A wireless device comprising: an antenna for receiving a wireless signal; an audio amplification system configured to amplify an input signal representative of the wireless signal, the audio amplification including an output stage operable with a series of pulses, the output stage having an output node; a low voltage system including a capacitor between the output node of the amplification stage and ground, the low voltage system further including a monitoring circuit configured to monitor a voltage at the capacitor against a desired low voltage value, low voltage system further including a control system configured to control charging and discharging of the capacitor based on an output of the monitoring circuit to regulate the voltage at the output node at approximately the desired low voltage value; and a speaker coupled to the output node of the output stage and configured to generate sound waves based on the amplified signal from the audio amplification system. ### Claim 15 (depends on 14) The wireless device of claim 14 wherein the wireless device is a wireless headphone or a wireless earphone.