BTL Power Amplifier Switching for Low-Heat Car Audio Output
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Solution Overview
Problem
Conventional power amplifying devices for car audio equipment face challenges in reducing heat generation and current consumption, especially with multi-stage vertical configurations, which limit their efficiency and lead to reduced lifespan of semiconductor devices due to heat damage.
Innovation Solution
The implementation of a power amplifying device with multiple BTL amplifiers and switch circuits that adjust their operation modes based on input signal amplitudes, using control circuits to manage common mode voltages and switch states, allowing for efficient power management and reduced power consumption across different signal modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a multi-stage vertical configuration is used with a single power supply rail, then the device complexity is reduced and installation space is optimized, but the voltage applied to each bridge amplifier is limited by the bias voltage range, making it difficult to achieve bridge amplification and further reduce consumed current
Solution Approach 1:
The invention divides the single power supply rail into multiple independent power supply rails (first power supply rail and second power supply rail). Each bridge amplifier can be independently powered, allowing the voltage applied to each bridge amplifier to exceed the bias voltage range. This segmentation enables bridge amplification while maintaining the compact multi-stage vertical configuration.
2Area of stationary object
If conventional power amplifying devices are used with B-class or AB-class bridge circuit configuration, then the device can be installed in limited space, but heat radiating devices cannot be adequately installed and semiconductor devices are damaged by heat with reduced lifetime
Solution Approach 1:
The invention changes the operational parameters of the power amplifying device by using multiple power supply rails with different voltage levels. This parameter change enables the device to operate in a manner that reduces power consumption and heat generation, while still achieving the required output power in a compact form factor suitable for car audio equipment.
3Use of energy by moving object
If the power supply voltage is low in multi-stage vertical configuration, then the consumed current is reduced, but the voltage applied to the bridge amplifier is also low and it is difficult to achieve bridge amplification
Solution Approach 1:
The invention segments the power supply system into multiple independent rails, allowing each bridge amplifier to receive adequate voltage from its dedicated power supply rail while the overall system maintains low current consumption. This is achieved by configuring multiple power supply rails with appropriate voltage levels for each stage.
Solution Approach 2:
The invention transitions from a single-dimensional power supply approach (single rail) to a multi-dimensional approach (multiple rails with different voltage levels). This dimensional change allows the system to simultaneously achieve low current consumption and sufficient voltage for bridge amplification by operating in a multi-rail voltage space.
Data Source
AI summary
A power amplifying device according to an embodiment includes first to fourth BTL amplifiers and first to third switch circuits. The first to fourth BTL amplifiers outputs a first to fourth output signal. The first switch circuit is turned on or off connection between an output of the second output amplifier and an output of the third output amplifier. The second switch circuit is turned on or off connection between an output of the fifth output amplifier and an output of the eighth output amplifier. The third switch circuit is turned on or off connection between an output of the fourth output amplifier and an output of the seventh output amplifier. The first to third switch circuits are turned on when the amplitudes of the first to fourth input signals are smaller than a first threshold.