Variable Power Voltage Supply for Mobile Audio Amplifiers
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Solution Overview
Problem
Conventional mobile devices with D-class switching power amplifiers face issues with abrupt loud sound output due to higher external power voltage, potential hearing damage, and susceptibility to noise, as well as limited high output power capability from internal loud speakers.
Innovation Solution
A variable power voltage supply system for mobile devices, incorporating a volume control unit and DC-DC converter to adaptively adjust power voltage to the switching power amplifier, allowing for enhanced signal-to-noise ratio and high output power when an external power supply is connected, while minimizing noise influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a higher level external power voltage is supplied to the D-class amplifier, then the output power is improved, but the user may experience abrupt loud sound and hearing damage
Solution Approach 1:
The patent implements dynamic voltage switching that adapts the power supply voltage to the D-class amplifier based on the operational state. When an external power supply is detected, the system dynamically selects between first power voltage (lower, for safety) and second power voltage (higher, for maximum output), thereby optimizing output power while preventing harmful abrupt loud sounds through real-time voltage adjustment
Solution Approach 2:
The system changes the power voltage parameter supplied to the D-class amplifier based on detection results. A detection unit identifies whether an external power supply is connected, and based on this detection, the power voltage parameter is switched between different levels, allowing the amplifier to operate at optimal power output without producing harmful abrupt sounds
2Device complexity
If a conventional external power supply unit is used, then the power supply is simple, but the system is susceptible to noises and cannot guarantee safety
Solution Approach 1:
The power supply system is segmented into multiple functional units: a detection unit that identifies external power supply connection, a control unit that determines operational state, and a power supply unit that provides different voltages. This segmentation allows the system to maintain simple overall structure while achieving noise immunity and safety through specialized functional divisions
Solution Approach 2:
The patent introduces an intermediary detection and control mechanism between the external power supply and the D-class amplifier. This intermediary system detects power supply connection status and mediates the voltage level supplied to the amplifier, thereby protecting against noise susceptibility and safety issues without requiring complex power supply circuitry
3Power
If the internal loud speaker is driven by high output power, then the sound quality is improved, but the internal loud speaker cannot achieve high output power due to its structural characteristic
Solution Approach 1:
The system dynamically adjusts the power voltage supplied to the D-class amplifier based on the connected audio output device. When an external audio device is detected, the system provides higher power voltage to enable high output power capability. When only an internal loud speaker is connected, the system provides lower power voltage appropriate for the loud speaker's structural characteristics, thereby achieving adaptability across different output devices
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
The system effectively controls volume and improves signal-to-noise ratio by using a boosted voltage with an external power supply, enabling high output power for loud speakers without noise interference from external power sources.
Implementation Method 1
a DC-DC converter unit to convert a voltage of an internal power supply into a DC-DC voltage in a variable manner on the basis of the voltage control value
Implementation Method 2
modulating a digital audio signal into a pulse width modulation (PWM) signal, performing power switching on the PWM signal on the basis of the voltage control value
Data Source
AI summary
A method and apparatus to supply a power voltage to a mobile device in a variable manner in order to provide high output power and a high quality sound environment and a mobile device using the same. The apparatus includes a volume control unit to detect installation of an external power supply and to generate a voltage control value corresponding to a current volume level, and a DC-DC converter unit to convert a voltage of an internal power supply in a variable manner on the basis of the voltage control value generated in the volume control unit in order to drive the switching power amplifier.