Reconfigurable Output Stage for Audio Subsystems

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing audio subsystems in portable devices waste die area and incur extra costs due to the need for separate output stages for Class-D amplifiers and DC-DC boost converters, which are not fully utilized in all audio configurations.

Innovation Solution

A reconfigurable output stage that can operate in multiple states, allowing it to be shared between Class-D amplifiers and DC-DC boost converters, utilizing a configurable input/output terminal structure with switches to adapt to different operating configurations, thereby optimizing die area usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate output stages are used for Class-D amplifier and DC-DC boost converter, then each component can operate independently in its optimized configuration, but die area is wasted and subsystem costs increase

Engineering Contradiction:
Improvecomponent operation reliabilityVSAvoiddie area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The output stage is designed as a universal circuit that can function as both a Class-D amplifier output stage and a DC-DC boost converter output stage. The same output stage circuitry is shared between these two functions through reconfigurable switching networks, eliminating the need for separate dedicated output stages for each component and thereby reducing die area while maintaining reliable operation for both functions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The output stage incorporates reconfigurable switching networks that dynamically reconfigure the circuit topology based on the operating mode (Class-D amplifier mode or DC-DC boost converter mode). This dynamic reconfiguration allows the same hardware to adapt its electrical characteristics and connection topology to match the requirements of different operating modes, enabling one output stage to serve multiple purposes.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If separate output stages are used for Class-D amplifier and DC-DC boost converter, then each component has dedicated hardware, but subsystem costs increase due to extra components

Engineering Contradiction:
Improveaudio configuration adaptabilityVSAvoidsubsystem component count
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The output stage serves as a universal circuit that can be shared between Class-D amplifier and DC-DC boost converter functions. By designing the output stage with reconfigurable switching networks, the same hardware infrastructure supports multiple audio configurations and power management modes, thereby reducing the total component count and subsystem complexity while maintaining the adaptability needed for different operating scenarios.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the output stage functions of the Class-D amplifier and DC-DC boost converter into a single shared circuit. The reconfigurable switching networks allow the same output stage hardware to be dynamically assigned to different functions based on system requirements, combining what would traditionally require separate dedicated circuits into one integrated solution.

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by moving object

If DC-DC boost converter is not used in medium loudness configuration, then battery power is sufficient, but the unused boost converter output stage wastes die area

Engineering Contradiction:
Improvebattery power efficiencyVSAvoidunused die area
Core Design Contradiction:
Use of energy by moving objectVSArea of stationary object

Solution Approach 1:

The output stage is designed as a universal circuit that can be shared between Class-D amplifier and DC-DC boost converter functions. By designing the output stage with reconfigurable switching networks, the same hardware infrastructure supports multiple audio configurations and power management modes, thereby reducing the total component count and subsystem complexity while maintaining the adaptability needed for different operating scenarios.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The output stage incorporates reconfigurable switching networks that dynamically reconfigure the circuit topology based on the operating mode (Class-D amplifier mode or DC-DC boost converter mode). This dynamic reconfiguration allows the same hardware to adapt its electrical characteristics and connection topology to match the requirements of different operating modes, enabling one output stage to serve multiple purposes.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2811646B1Reconfigurable output stage
Publication Date: 2018.12.26 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2811646B1 patent drawingFigure 1~2
  • EP2811646B1 patent drawingFigure 3~4
  • EP2811646B1 patent drawingFigure 5~6

AI summary

A circuit comprising: - an output stage according to the invention; - a first control apparatus comprising a control stage of the first control apparatus is connected to the output stage; and, - a second control apparatus comprising a control stage of the second control apparatus is connected to the output stage; wherein, - when the control stage of the first control apparatus is connected to the output stage, the control stage of the second control apparatus is electrically disconnected from the output stage, the output stage being configured to operate in a first operating state; and, - when the control stage of the second control apparatus is connected to the output stage, the control stage of the first control apparatus is electrically disconnected from the output stage, the output stage being configured to operate in a second operating state. The output stage and the use of the output stage are also claimed.