Dynamic Supply Voltage Control for Low-Distortion Amplifiers
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Solution Overview
Problem
Existing amplifier designs, such as Class D, G, and H amplifiers, face inefficiencies and distortion due to large FET sizes and abrupt rail switching, necessitating the development of more efficient amplifier systems with dynamically adjusted supply voltages.
Innovation Solution
An amplifier system with a dynamic power supply control system that adjusts first and second supply voltages based on the input signal, maintaining a substantially constant difference between them, to optimize power delivery and reduce distortion across various amplifier classifications like Class A, B, and AB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If Class D amplifier uses switching mode transistors to regulate power delivery, then power conversion efficiency is improved, but very large FET sizes are required to achieve high efficiencies and lower resistance at turn on
Solution Approach 1:
The patent applies dynamics by continuously varying the supply voltage to the output stage in real-time based on the signal level. The supply voltage is dynamically adjusted from a minimum bias level up to higher levels as needed, allowing the amplifier to operate efficiently at low signal levels while maintaining the capability for high power output when required. This dynamic supply voltage adjustment eliminates the need for large FET sizes required in fixed Class D designs.
Solution Approach 2:
The patent changes the supply voltage parameter continuously rather than using fixed rails. By modulating the supply voltage amplitude according to the signal requirements, the amplifier can achieve high efficiency operation with smaller transistors. The supply voltage parameter is transformed from a static value to a dynamically controlled variable, resolving the contradiction between efficiency and device size.
2Loss of energy
If Class G amplifier employs rail switching to reduce power consumption, then efficiency is improved, but abrupt switching causes distortion
Solution Approach 1:
The patent replaces abrupt rail switching with continuous supply voltage modulation. Instead of suddenly switching between discrete voltage rails, the supply voltage is dynamically adjusted in a continuous manner that follows the signal envelope. This dynamic approach maintains the power consumption benefits of variable supply voltage while eliminating the distortion caused by abrupt transitions.
Solution Approach 2:
The supply voltage is modulated in periodic synchronization with the signal cycles. The voltage adjustments occur rhythmically in response to the signal characteristics, ensuring that power is supplied efficiently during active periods while maintaining signal integrity. This periodic modulation pattern prevents the distortion associated with irregular rail switching.
3Loss of energy
If Class H amplifier continuously boosts and lowers the supply above minimum bias level, then efficiency is improved, but complexity of power supply control increases
Solution Approach 1:
The patent implements a dynamically controlled power supply system that adjusts voltage levels based on real-time signal conditions. The control system monitors signal levels and continuously adapts the supply voltage accordingly, achieving high efficiency through dynamic operation. While this adds control complexity, it provides superior efficiency compared to static designs and manages the complexity through integrated control circuitry.
Solution Approach 2:
The power supply control system uses feedback from the signal path to adjust supply voltage levels. The control mechanism monitors amplifier operation and signal requirements, then feeds this information back to the power supply to optimize voltage delivery. This feedback loop enables efficient operation while managing control complexity through intelligent regulation rather than simple switching.
Data Source
AI summary
An amplifier system may include an output stage configured to provide an amplified output signal at an output thereof based on an input signal, the output stage being connected between first and second supply voltages. A dynamic power supply control system provides the first and second supply voltages, the dynamic power supply being configured to adjust the first and second supply voltages as a function of the input signal such that a difference between the first and second supply voltages remains substantially constant.