Vehicle Infotainment Audio Amplifier Power Management
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Solution Overview
Problem
Infotainment systems in vehicles face high power consumption when not in use and lack convenient on/off switching options, making them inefficient and vulnerable to theft due to their fixed nature.
Innovation Solution
A controllable audio reproduction system with a wireless connection between a fixed audio reproduction arrangement and a portable device, utilizing transceivers for bidirectional communication, and an operational amplifier with two branches of transistors that can switch between active and inactive states to manage quiescent current, allowing for reduced power consumption and easy portability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the audio reproduction arrangement is fixed in the vehicle with high power consumption components, then reliable audio output is achieved, but power consumption becomes excessively high when not in use
Solution Approach 1:
The amplifier's output stage is designed to dynamically switch between active and inactive states. The switching circuit responds to control signals from the portable device, enabling the amplifier to adapt its power consumption level based on whether audio playback is currently needed, thus resolving the contradiction between reliable audio output and excessive power consumption.
Solution Approach 2:
The system employs periodic switching of the amplifier stages based on usage patterns. When the portable device is not actively controlling audio playback, the amplifier stages are switched off. When playback is required, they are activated. This periodic on/off action allows the system to maintain reliability when needed while minimizing power consumption during idle periods.
2Use of energy by moving object
If separate on/off switches are added to the fixed device, then power consumption can be reduced, but device complexity and inconvenience increase
Solution Approach 1:
The system implements self-service switching where the portable device automatically controls the activation of the fixed audio reproduction arrangement. The wireless communication between devices enables the portable device to send control signals that automatically switch the amplifier stages on or off based on whether audio playback is required, eliminating the need for manual switches and providing convenient power management.
Solution Approach 2:
The wireless control system acts as an intermediary between the user's intent (to play or stop audio) and the physical state of the amplifier. Instead of requiring direct manual switching, the system uses wireless communication protocols to mediate the control signal transmission, automatically translating user actions on the portable device into appropriate power state changes in the fixed arrangement.
3Reliability
If the head unit is densely integrated into the vehicle, then theft protection is improved, but adaptability and portability are reduced
Solution Approach 1:
The audio system is segmented into two distinct parts: a fixed, integrated audio reproduction arrangement that remains in the vehicle for security, and a portable control device that can be freely moved. This segmentation allows the system to maintain theft protection through the fixed component while gaining portability and adaptability through the separate portable device that can be used with different vehicles or taken elsewhere.
Solution Approach 2:
The portable device serves multiple functions: it acts as a remote control, a power management interface, and potentially a media source. By making this component universal and portable, the system gains versatility - the same portable device can control audio in different vehicles or be used in various contexts, while the fixed arrangement maintains its security 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
The system achieves reduced power consumption when not in use and provides protection against theft by allowing the portable device to control audio functions wirelessly, enhancing user convenience and security.
Implementation Method 1
The audio reproduction arrangement has an amplification, a quiescent power consumption and a maximum output power. The audio reproduction arrangement includes an operational amplifier and two branches, wherein each of the branches includes four transistors
Implementation Method 2
A second transistor is connected to a preamplifier, wherein the preamplifier is configured to be controlled by the control signal and to switch, in accordance with the control signal, the pair of transistors of the branches active or inactive. The audio reproduction arrangement has a maximum quiescent current when the pairs of transistors of the branches are switched active, and a reduced quiescent current when the pair of transistors of the branches are switched inactive
Implementation Method 3
a wireless connection between the portable device and the audio reproduction arrangement configured to transmit the audio and control signals from the portable device to the audio reproduction arrangement
Implementation Method 4
Controlling switching includes low-pass filtering of the control signal as input to the preamplifier, wherein the low-pass filtered control signal is used to switch with a switching slope adapted to produce no audible artifacts in the acoustically reproduced audio signal
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
An infotainment system for a vehicle may include a controllable audio reproduction arrangement that is configured to be fixed in the vehicle and to acoustically reproduce an audio signal under the control of a control signal. It may further include a portable device that is freely movable in the vehicle and that is configured to provide the audio and control signals for the audio reproduction arrangement, as well as a wireless connection between the portable device and the audio reproduction arrangement configured to transmit the audio and control signals from the portable device to the audio reproduction arrangement. The audio reproduction arrangement has amplification, quiescent power consumption and a maximum output power, of which at least one is controllable by the portable device via the control signal.