Adaptive Feed-Forward Amplifier Supply Control for Low Distortion
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Solution Overview
Problem
Conventional power converter circuits for amplifiers are inefficient due to fixed switching frequency and output voltage, leading to signal-dependent voltage droop and distortion, especially when load power requirements vary over time.
Innovation Solution
A digital amplifying circuitry system that delays digital data signals to detect signal amplitude information, converting it into control signals to adjust the power converter's switching frequency and voltage, ensuring sufficient supply current and voltage to prevent distortion while optimizing power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed switching frequency and output voltage amplitude are used to meet worst-case load conditions, then the amplifier can provide sufficient power during peak demand, but the power converter dissipates excessive power during low-demand periods
Solution Approach 1:
The patent applies dynamics by making the power converter's switching frequency variable rather than fixed. The switching frequency is dynamically adjusted based on the instantaneous power requirements of the amplifier, allowing the system to operate efficiently at lower frequencies during low-demand periods while maintaining sufficient power delivery capability during peak demand periods.
Solution Approach 2:
The patent changes the operating parameters of the power converter, specifically the switching frequency and output voltage amplitude, to match the actual power requirements of the amplifier. By monitoring the amplifier's power consumption and adjusting these parameters accordingly, the system avoids the energy waste associated with fixed high-frequency operation while ensuring adequate power supply during peak loads.
2Loss of energy
If the power converter switching frequency and output voltage amplitude are reduced to improve power efficiency, then power dissipation decreases, but the power converter cannot meet peak load demands causing voltage droop and signal distortion
Solution Approach 1:
The patent employs feedback by continuously monitoring the amplifier's power consumption and using this information to adjust the power converter's switching frequency and output voltage amplitude. This closed-loop control ensures that the power converter responds to changing load conditions, maintaining voltage stability and preventing distortion while optimizing power efficiency.
Solution Approach 2:
The patent applies preliminary action by proactively adjusting the power converter's parameters in response to detected amplifier power requirements. Rather than reacting to voltage droop after it occurs, the system anticipates power needs and adjusts switching frequency and voltage amplitude beforehand, preventing distortion before it happens.
3Loss of energy
If feedback control is used to adjust amplifier supply voltage based on output signal amplitude, then power consumption efficiency improves, but feedback lag causes delay in voltage adjustment resulting in signal distortion
Solution Approach 1:
The patent introduces an intermediary mechanism by using a buffer or storage element that decouples the feedback control loop from the voltage adjustment process. This intermediary allows the control system to process power requirement information and generate appropriate switching frequency commands without introducing significant delay, thereby maintaining both power efficiency and fast response capability.
Data Source
AI summary
Digital amplifying circuitry delays a digital data signal (INR) to produce an output signal (VoutR). The delayed digital data signal is converted to an analog signal (VinR) for amplifying by an amplifier (10R). Signal amplitude information (S_R[n]) contained in the incoming digital data signal is detected during the delaying. The signal amplitude information is converted to a first control signal (S_Io_NEG[n]) in response to which an adjustable maximum available supply current of the amplifier is produced of least sufficient magnitude to avoid distortion during the amplifying to produce the output signal. The signal amplitude information also is converted to a second control signal (S_AMPLITUDE[n]) in response to which a supply voltage (VNEG) of the amplifier is controlled.