Series-Coupled Full-Bridge Audio Amplifiers for High-Voltage Output

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Solution Overview

Problem

High voltage audio amplifiers require discrete power transistors to handle high voltage levels, leading to size, weight, and power loss issues, and existing solutions necessitate multiple isolated power supplies and complex signal isolation, increasing costs and complexity.

Innovation Solution

A power amplifier system using standard off-the-shelf monolithic power devices with integrated protection schemes, reducing the need for electrical isolation and isolated power supplies, and implementing a serial link of identical full-bridge amplifiers with one sharing common ground and the other being electrically isolated, to achieve high voltage output with low voltage building blocks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If discrete power transistors are used to handle high voltage levels, then high voltage output is achieved, but size, weight, and power loss increase

Engineering Contradiction:
Improvehigh voltage outputVSAvoidpower loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent divides the high voltage amplifier into multiple low voltage amplifier modules connected in series. Each module operates at low voltage (e.g., 32V RMS) but the series connection of multiple modules achieves the desired high voltage output (e.g., 70V RMS or higher). This segmentation allows using standard monolithic power devices instead of high voltage discrete transistors, reducing power loss while maintaining high voltage capability.

Inventive Principle:
Principle #1Segmentation

2Power

If discrete power transistors are used to handle high voltage levels, then high voltage output is achieved, but size and weight increase

Engineering Contradiction:
Improvehigh voltage outputVSAvoidamplifier weight
Core Design Contradiction:
PowerVSWeight of stationary object

Solution Approach 1:

The amplifier is segmented into multiple identical low voltage modules that can be stacked in series. Each module uses standard monolithic power devices which are much lighter than discrete high voltage transistors. The modular architecture allows achieving high voltage output through series connection of lightweight modules rather than using heavy discrete high voltage components.

Inventive Principle:
Principle #1Segmentation

3Power

If multiple isolated power supplies are used to achieve high voltage output, then voltage requirement is met, but device complexity increases

Engineering Contradiction:
Improvehigh voltage outputVSAvoidpower supply complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent merges multiple low voltage power supplies into a series-connected configuration where their outputs are相加 to achieve high voltage. Instead of using completely isolated power supplies for each module, the design allows sharing of common ground references and simplifies the power supply architecture by combining multiple low voltage sources to create the high voltage output, reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If electrical isolation is implemented between amplifier modules, then safety is improved, but signal transfer complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidsignal isolation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent establishes a common ground reference (equipotential) across all amplifier modules, eliminating the need for complex electrical isolation and signal transfer mechanisms. By maintaining all modules at the same ground potential, simple wire connections can be used for signal and power transfer between modules, while safety is maintained through the inherent low voltage operation of each individual module.

Inventive Principle:
Principle #12Equipotentiality

Data Source

PatentEP3041134B1Power amplifiers coupled in series
Publication Date: 2021.06.02 MUSIC GROUP IP
  • EP3041134B1 patent drawingFigure 1~2
  • EP3041134B1 patent drawingFigure 3
  • EP3041134B1 patent drawingFigure 4

AI summary

A power amplifier system is disclosed, the power amplifier system comprising two power supplies (1041,1042), four amplifier half-bridges arranged as two amplifier full bridges (1031,1032), and an audio processor (1050) for establishing control signals for the amplifier full-bridges, where the audio processor and one of the power supplies share a common ground potential (1010), whereas the other power supply has a floating ground (1020); wherein both the amplifier with common ground and the amplifier with floating ground have an amplifier interconnection output (1037) and an amplifier output, and wherein the amplifier interconnection outputs are connected, and a load (1008) is connected to the amplifier outputs (1033,1035). Further are disclosed amplification methods and PA systems correspondingly.