# US 9,520,843 B2 · Power amplifiers coupled in series > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,843 B2 - Document ID: US9520843B2 - Status: Granted - Kind: B2 - Application number: 14/589,128 - Filed: 2015-01-05 - Published: 2016-07-07 - Granted: 2016-12-13 - Earliest claimed: 2015-01-05 - Assignees: MUSIC Group IP Ltd. - Applicants: The TC Group A/S - Inventors: Lars Arknaes-Pedersen - Web page: https://patentgrep.com/patent/US9520843B2 ## CPC - H03F 1/565: {using inductive elements} - H03F 1/0283: {Reducing the number of DC-current paths} - H03F 3/183: with semiconductor devices only - H03F 3/187: in integrated circuits - H03F 3/211: {using a combination of several amplifiers (H03F3/60 takes precedence)} - H03F 3/217: Class D power amplifiers; Switching amplifiers - H03F 3/2173: {of the bridge type} - H04R 27/00: Public address systems (circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; {monitoring or testing arrangements for public address systems H04R29/007}; amplifiers H03F) - H03F 2200/03: the amplifier being designed for audio applications - H03F 2200/189: the ground, reference or shield potential difference between different chips being controlled - H03F 2200/321: Use of a microprocessor in an amplifier circuit or its control circuit - H03F 2200/351: Pulse width modulation being used in an amplifying circuit - H03F 2203/21142: Output signals of a plurality of power amplifiers are parallel combined to a common output - H03F: AMPLIFIERS - 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 A power amplifier system is disclosed, the power amplifier system comprising two power supplies, four amplifier half-bridges arranged as two amplifier full bridges, and an audio processor for establishing control signals for the amplifier full-bridges, where the audio processor and one of the power supplies share a common ground potential, whereas the other power supply has a floating ground; wherein both the amplifier with common ground and the amplifier with floating ground have an amplifier interconnection output and an amplifier output, and wherein the amplifier interconnection outputs are connected, and a load is connected to the amplifier outputs. Further are disclosed amplification methods and PA systems correspondingly. ## Claims ### Claim 1 A power amplifier system comprising an audio processor comprising an audio input and a control output; a first amplifier full bridge connected to a first power supply; and a second amplifier full bridge connected to a second power supply; wherein an amplifier interconnection output of said first amplifier is connected to an amplifier interconnection output of said second amplifier; wherein said first amplifier and said second amplifier each comprises an amplifier output for a load to be connected in between; wherein said first power supply and said audio processor has a common ground potential and said first amplifier is connected to said control output; wherein said second power supply is floating with respect to said common ground potential and said second amplifier is connected to said control output through an isolation barrier. ### Claim 2 (depends on 1) The power amplifier system of claim 1, wherein said first amplifier full bridge and said second amplifier full bridge are integrated on a single-chip device comprising at least four amplifier half-bridges. ### Claim 3 (depends on 1) The power amplifier system of claim 1, wherein said first power supply and said second power supply are arranged to supply no more than 80V DC potential from rail-to-rail of each power supply. ### Claim 4 (depends on 1) The power amplifier system of claim 1, wherein said first amplifier full bridge and said second amplifier full bridge together comprise four amplifier half-bridges, and wherein a rail-to-rail supply voltage to each amplifier half-bridge is no more than 80V. ### Claim 5 (depends on 1) The power amplifier system of claim 1, wherein the first amplifier full bridge and the second amplifier full bridge are implemented as Class-D amplifiers. ### Claim 6 (depends on 5) The power amplifier system of claim 5, wherein the Class-D amplifiers are open-loop Class-D amplifiers. ### Claim 7 (depends on 6) The power amplifier system of claim 6, wherein the open-loop Class-D amplifiers are based on discrete-time modulation. ### Claim 8 (depends on 5) The power amplifier system of claim 5 arranged to establish a multi-level Class-D modulation. ### Claim 9 (depends on 8) The power amplifier system of claim 8, wherein said multi-level Class-D modulation comprises five levels. ### Claim 10 (depends on 1) The power amplifier system of claim 1 comprising no more than three power inductors. ### Claim 11 (depends on 1) The power amplifier system of claim 1, wherein the isolation barrier comprises optical isolation. ### Claim 12 (depends on 1) The power amplifier system of claim 1, wherein the isolation barrier comprises transformer isolation. ### Claim 13 (depends on 1) The power amplifier system of claim 1, wherein the isolation barrier comprises capacitive isolation. ### Claim 14 (depends on 1) The power amplifier system of claim 1, wherein the isolation barrier comprises RF isolation. ### Claim 15 (depends on 1) The power amplifier system of claim 1, where said first amplifier full bridge and said second amplifier full bridge are arranged on a common printed circuit board. ### Claim 16 (depends on 1) The power amplifier system of claim 1, wherein said first power supply and said second power supply share a common transformer core. ### Claim 17 (depends on 1) The power amplifier system of claim 1, wherein said connection between said first amplifier full bridge and said first power supply comprises a positive DC rail and a negative DC rail, and said connection between said second amplifier full bridge and said second power supply comprises a positive DC rail and a negative DC rail. ### Claim 18 (depends on 1) The power amplifier system of claim 1, wherein said connection between said first amplifier full bridge and said first power supply comprises a positive DC rail and said common ground potential, and said connection between said second amplifier full bridge and said second power supply comprises a positive DC rail and a floating ground potential. ### Claim 19 (depends on 1) The power amplifier system of claim 1, wherein the potential of a positive DC rail of said first power supply compared to said common ground potential corresponds to the potential of a positive DC rail of said second power supply compared to said floating ground potential. ### Claim 20 (depends on 1) The power amplifier system of claim 1, wherein said audio processor comprises a PWM modulator. ### Claim 21 (depends on 1) The power amplifier system of claim 1, wherein said control output comprises one or more first amplifier control signals and one or more second amplifier control signals. ### Claim 22 (depends on 1) The power amplifier system of claim 1, wherein said control output comprises an audio signal. ### Claim 23 A high voltage audio amplification method comprising providing an audio processor comprising an audio input and a control output and a first power supply having at least a positive DC rail; arranging the audio processor and the first power supply with a common ground potential; providing a second power supply having at least a positive DC rail; arranging the second power supply with a floating ground potential; providing a first amplifier full bridge and connecting it to the first power supply and the control output of the audio processor; providing a second amplifier full bridge and connecting it to the second power supply; providing an isolation barrier and establishing a connection between the control output of the audio processor and the second amplifier full bridge through said isolation barrier; arranging an amplifier interconnection between an amplifier interconnection output of said first amplifier and an amplifier interconnection output of said second amplifier; coupling a load between an amplifier output of said first amplifier and an amplifier output of said second amplifier; providing at said audio input of said audio processor an audio signal to be amplified to high voltage. ### Claim 24 (depends on 23) The high voltage audio amplification method of claim 23, comprising providing said first amplifier full bridge and said second amplifier full bridge on a single-chip device comprising at least four amplifier half-bridges. ### Claim 25 (depends on 23) The high voltage audio amplification method of claim 23, wherein said first power supply and said second power supply are arranged to supply no more than 80V DC potential from rail-to-rail of each power supply. ### Claim 26 (depends on 23) The high voltage audio amplification method of claim 23, wherein said first amplifier full bridge and said second amplifier full bridge are provided as a total of four amplifier half-bridges, and wherein a rail-to-rail supply voltage to each amplifier half-bridge is no more than 80V. ### Claim 27 (depends on 23) The high voltage audio amplification method of claim 23, comprising providing said first amplifier full bridge and said second amplifier full bridge as Class-D amplifiers. ### Claim 28 (depends on 23) The high voltage audio amplification method of claim 23, comprising performing PWM modulation in said audio processor. ### Claim 29 (depends on 23) The high voltage audio amplification method of claim 23, comprising establishing a multi-level Class-D modulation. ### Claim 30 (depends on 23) The high voltage audio amplification method of claim 23, wherein the isolation barrier performs capacitive isolation. ### Claim 31 (depends on 23) The high voltage audio amplification method of claim 23, comprising providing said first power supply and said second power supply on a common transformer core. ### Claim 32 A public address system comprising a power amplifier system comprising an audio processor comprising an audio input and a control output; a first amplifier full bridge connected to a first power supply; and a second amplifier full bridge connected to a second power supply; wherein an amplifier interconnection output of said first amplifier is connected to an amplifier interconnection output of said second amplifier; wherein said first amplifier and said second amplifier each comprises an amplifier output for a load to be connected in between; wherein said first power supply and said audio processor has a common ground potential and said first amplifier is connected to said control output; wherein said second power supply is floating with respect to said common ground potential and said second amplifier is connected to said control output through an isolation barrier; and wherein said public address system further comprises an audio source input connected to said audio input and two or more loudspeakers coupled to said amplifier outputs in parallel connection with each other.