Single-Ended Switching Power Stage for Audio Amplifiers
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Solution Overview
Problem
Existing audio device speaker drivers face issues with electromagnetic interference, power efficiency, and handling large impulsive signals due to their switching nature, which can lead to signal clipping and incompatibility with other audio circuits.
Innovation Solution
A switching power stage with a power converter and controller that sequentially operates in multiple switch configurations, allowing for adaptive selection of operational modes such as buck and boost configurations to manage energy transfer efficiently and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a full-bridge output stage with LC filters is used to reduce electromagnetic interference, then electromagnetic radiation is mitigated, but the filter size becomes large and power efficiency deteriorates
Solution Approach 1:
The patent extracts and eliminates the large LC filters from the output stage by using a single-ended switching architecture that inherently reduces electromagnetic radiation. The harmful filtering components are removed while maintaining EMI reduction through the switching topology itself, thereby improving power efficiency without large filters.
Solution Approach 2:
The patent replaces the traditional full-bridge switching mechanism with a single-ended switching architecture. This substitution changes the fundamental switching approach, reducing electromagnetic radiation at the source and eliminating the need for large LC filters, thus improving both EMI performance and power efficiency.
2Loss of energy
If power supply voltage is varied to reduce power consumption, then power efficiency is improved, but large impulsive signals cause signal clipping
Solution Approach 1:
The patent implements dynamic switching between different operational modes (buck, boost, and bypass modes) based on the instantaneous signal conditions. This dynamic adaptation allows the system to maintain low power consumption during normal operation while quickly responding to large impulsive signals without clipping, resolving the contradiction between power efficiency and signal handling capability.
Solution Approach 2:
The patent changes the operational parameters of the power converter by switching between different modes (buck for voltage reduction, boost for voltage increase, bypass for direct connection). These parameter changes enable the system to adapt to varying signal conditions, maintaining both low power consumption and high signal handling capability.
3Loss of energy
If envelope-tracking boost converter is used before full-bridge output stage, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The patent creates a multi-functional single-ended switching power converter that can operate in multiple modes (buck, boost, bypass) within a single unified architecture. This universal design eliminates the need for separate envelope-tracking and full-bridge stages, reducing device complexity while maintaining power efficiency through mode selection based on operating conditions.
Solution Approach 2:
The patent merges the functions of envelope-tracking and full-bridge output stages into a single integrated single-ended switching power converter. By combining these previously separate stages into one unified structure with multiple operational modes, the patent reduces overall device complexity while preserving power efficiency benefits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces electromagnetic interference, improves power efficiency, and effectively handles large impulsive signals without causing signal clipping, ensuring compatibility with various audio circuits.
Implementation Method 1
a power inductor, a plurality of switches, an output, and at least one capacitor arranged as shown
Implementation Method 2
such LC filters are often quite large in size, and coupling capacitors 122 and 124 to the terminals of the output transducer
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
A switching power stage for producing an output voltage to a load may include a power converter and a controller. The power converter may include a power inductor and plurality of switches arranged to sequentially operate in a plurality of switch configurations. The controller may be configured to, based on a measured parameter associated with the switching power stage, select a selected operational mode of the power converter from a plurality of operational modes, and sequentially apply switch configurations from the plurality of switch configurations to selectively activate or deactivate each of the plurality of switches in order to transfer electrical energy from an input source of the power converter to the load in accordance with the selected operational mode.