Configurable Modal Amplifier With Dynamic Rail Modulation
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Solution Overview
Problem
Linear amplifiers, such as class A, are inefficient at low signal levels, while switching amplifiers, like class D, sacrifice fidelity for efficiency, and existing methods to improve efficiency of linear amplifiers by modulating rail voltages are limited in effectively balancing efficiency and fidelity across varying signal levels.
Innovation Solution
A configurable amplifier system where the power supply rails of a linear amplifier are modulated by a switching amplifier, allowing the system to operate in rail modulation mode to enhance efficiency at low signal levels and switch to signal amplification mode for higher fidelity, with adjustable delay circuitry and programmable parameters to optimize efficiency and fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linear amplifier (class A) is used to amplify audio signals, then high fidelity sound reproduction is achieved, but efficiency deteriorates particularly at low signal levels
Solution Approach 1:
The patent applies dynamics by making the power supply rail voltages dynamic rather than fixed. The rail voltages are continuously modulated to match the instantaneous signal level, allowing the amplifier to maintain high fidelity like class A while improving efficiency by reducing the average power consumption through continuous voltage adjustment.
Solution Approach 2:
The patent changes the parameter of power supply rail voltage from discrete levels to continuous modulation. By continuously varying the rail voltages based on the input signal amplitude, the system achieves both high fidelity (through sufficient voltage headroom) and high efficiency (through reduced average power dissipation).
2Use of energy by moving object
If switching topology (class D) is used to achieve high efficiency, then efficiency is improved but fidelity deteriorates
Solution Approach 1:
The patent uses continuous dynamic modulation of the power supply rails rather than discrete switching levels. This continuous modulation approach maintains the efficiency benefits of switching topologies while avoiding the fidelity degradation by providing smooth, analog-like voltage transitions that better preserve signal quality.
Solution Approach 2:
The patent transforms the discrete voltage levels characteristic of class D amplifiers into continuously modulated voltages. This parameter change from discrete to continuous voltage control allows the system to achieve high efficiency through switching-based power delivery while maintaining high fidelity through analog-quality voltage modulation.
3Use of energy by moving object
If rail voltages are modulated between discrete levels (class G) to improve efficiency, then efficiency is improved but the ability to balance efficiency and fidelity across varying signal levels is limited
Solution Approach 1:
The patent implements continuous dynamic modulation of rail voltages that responds in real-time to the instantaneous signal level, in contrast to the static discrete level switching of class G. This dynamic approach provides continuous adaptability across the entire signal range, allowing optimal efficiency-fidelity balance at any signal level rather than at discrete operating points.
Solution Approach 2:
The patent changes the modulation approach from discrete voltage levels to continuous voltage modulation. This enables the system to adapt continuously to varying signal levels, providing both efficiency improvements and enhanced adaptability across the full dynamic range of audio signals, rather than being constrained to fixed discrete operating points.
Data Source
AI summary
Configurable amplifier systems are described in which the power supply rail of a linear amplifier, e.g., a class A amplifier, is modulated by a switching amplifier, e.g., a class D amplifier, that may also be configured to operate independently of the linear amplifier. Techniques are also described by which the standing current of the output stage of a linear amplifier is modulated based on the input signal to the linear amplifier or based on modulation of the power supply rail of the linear amplifier.