Adjustable Amplifier Bypass Circuit for Supply Noise Attenuation
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Solution Overview
Problem
Amplifiers are adversely impacted by non-ideal power supply sources with non-zero output impedance and supply voltages containing noise and undesired signals, which affect their performance.
Innovation Solution
The implementation of an adjustable bypass circuit with variable capacitance or resistance elements between the power supply source and circuit ground to filter out noise and undesired signals, allowing for tuning of resonance frequency and quality factor to enhance amplifier stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed bypass circuit with fixed capacitance or resistance is used, then the circuit structure is simple, but the amplifier performance cannot be optimized for different operating conditions
Solution Approach 1:
The bypass circuit transitions from fixed components to dynamically adjustable components. The patent implements variable capacitance elements (such as switched capacitor arrays or variable capacitance diodes) and variable resistance elements (such as digitally controlled resistors) that can be adjusted in real-time to optimize amplifier performance across different operating conditions, frequencies, and signal levels.
Solution Approach 2:
The patent changes the electrical parameters of the bypass circuit by introducing adjustable capacitance and resistance values. Through digital control signals, the capacitance and resistance parameters can be varied to match different amplifier operating points, frequency ranges, and load conditions, thereby achieving parameter optimization without requiring multiple fixed circuits.
2Object-affected harmful factors
If no bypass circuit is used, then the device complexity is minimal, but noise and undesired signals from the power supply adversely impact amplifier performance
Solution Approach 1:
The bypass circuit acts as an intermediary element between the power supply source and the amplifier. By inserting adjustable capacitance and resistance components in parallel with the amplifier power supply connection, the circuit mediates the harmful noise and undesired signals from the power supply, filtering them out while maintaining the necessary power supply function.
Solution Approach 2:
The patent converts the harmful effect of power supply noise into a beneficial filtering function. By carefully selecting and adjusting the bypass capacitance and resistance values, the circuit creates a low-impedance path for noise frequencies while maintaining high-impedance for the desired DC supply voltage, thereby transforming the power supply's non-ideal characteristics into an opportunity for noise rejection.
3Manufacturing precision
If the bypass circuit uses fixed components, then the manufacturing precision requirements are lower, but the resonance frequency and quality factor cannot be tuned for optimal performance
Solution Approach 1:
The bypass circuit employs dynamically adjustable capacitance and resistance elements that can be controlled through digital signals. This allows the resonance frequency (ω₀ = 1/√(LC)) and quality factor (Q = R/ω₀L) to be precisely tuned by changing the capacitance and resistance values, eliminating the need for tight manufacturing tolerances on fixed components while achieving precise frequency and Q-factor control.
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
This approach improves the stability and performance of amplifiers by effectively attenuating noise and optimizing resonance frequencies, leading to better linearity and efficiency.
Implementation Method 1
The adjustable bypass circuit may include an adjustable capacitor
Implementation Method 2
The adjustable bypass circuit may include a fixed capacitor coupled to an adjustable resistor
Implementation Method 3
allowing for tuning of resonance frequency and quality factor to enhance amplifier stability and performance
Data Source
AI summary
Techniques for bypassing a supply voltage for an amplifier are disclosed. In an exemplary design, an apparatus includes an amplifier and an adjustable bypass circuit. The amplifier (e.g., a power amplifier) receives a supply voltage from a supply source. The adjustable bypass circuit is coupled to the supply source and provides bypassing for the supply voltage. The adjustable bypass circuit includes an adjustable capacitor or a fixed capacitor coupled to an adjustable resistor. The supply source may be (i) a power supply source providing a fixed supply voltage for the amplifier or (ii) an envelope tracker providing a variable supply voltage for the amplifier.