RF Amplifier Envelope Tracking Compensation for Parasitic Impedance
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Solution Overview
Problem
Conventional RF amplifier circuitry experiences reduced efficiency and increased distortion due to parasitic impedance between the envelope tracking power supply circuitry and the power amplifier circuitry, leading to errors in the envelope supply voltage, which existing solutions attempt to address by minimizing distance or integrating components, but these approaches are inflexible and costly.
Innovation Solution
The implementation of target envelope supply voltage compensation circuitry to compensate for the target envelope supply voltage, allowing the power amplifier envelope supply voltage to accurately track the envelope of the RF input signal by reducing errors caused by parasitic impedance through equalization, without necessarily reducing the parasitic impedance itself.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If envelope tracking power supply circuitry is provided as a separate die from power amplifier circuitry, then device flexibility and manufacturing cost are improved, but parasitic impedance increases causing voltage tracking errors
Solution Approach 1:
The patent implements a feedback mechanism where the actual envelope supply voltage at the power amplifier is measured and fed back to the envelope tracking power supply circuitry. This feedback loop enables the system to detect voltage deviations caused by parasitic impedance and dynamically adjust the output voltage to compensate for these drops, thereby maintaining accurate voltage tracking despite the separate die configuration.
Solution Approach 2:
The patent introduces an intermediary compensation circuit that acts as a mediator between the envelope tracking power supply circuitry and the power amplifier. This intermediary circuit includes components such as a compensation capacitor and resistor that form an RC network to generate a compensation voltage signal, which is then added to the target envelope voltage to pre-compensate for the voltage drop across parasitic impedance.
2Measurement precision
If distance between envelope tracking power supply circuitry and power amplifier circuitry is minimized, then parasitic impedance is reduced improving voltage tracking, but device complexity and manufacturing cost increase
Solution Approach 1:
The feedback mechanism allows the system to maintain accurate voltage tracking without requiring minimal physical distance between components. By continuously monitoring the actual voltage and adjusting the output accordingly, the system compensates for voltage drops caused by parasitic impedance, eliminating the need for tight layout constraints and reducing layout complexity.
Solution Approach 2:
The patent changes the operating parameters of the power supply circuitry by dynamically adjusting the output voltage based on measured conditions. Instead of relying on fixed physical proximity to maintain voltage accuracy, the system adapts its voltage output parameter in real-time to compensate for parasitic effects, thereby decoupling voltage tracking accuracy from physical layout constraints.
3Measurement precision
If integration of envelope tracking power supply circuitry and power amplifier circuitry is performed on a single die, then parasitic impedance is reduced improving voltage tracking, but manufacturing cost and device complexity increase
Solution Approach 1:
The feedback mechanism enables separate die configurations to achieve voltage tracking accuracy previously only attainable through integration. By measuring actual voltage at the power amplifier and feeding this information back to adjust the power supply output, the system compensates for parasitic impedance effects without requiring costly integration, thereby maintaining manufacturing flexibility and lower costs while achieving equivalent performance.
Data Source
AI summary
Radio frequency (RF) amplifier circuitry for amplifying an RF input signal to provide an RF output signal includes target envelope supply voltage compensation circuitry, envelope tracking power supply circuitry, and power amplifier circuitry. The target envelope supply voltage compensation circuitry is configured to compensate a target envelope supply voltage to provide a compensated target envelope supply voltage, which is used by the envelope tracking power supply circuitry to provide an output envelope supply voltage. The power amplifier circuitry is configured to amplify the RF input signal using a power amplifier envelope supply voltage. The power amplifier envelope supply voltage is different from the output envelope supply voltage due to a parasitic impedance. The target envelope supply voltage compensation circuitry is configured to compensate the target envelope supply voltage to reduce an error between the target envelope supply voltage and the power amplifier envelope supply voltage.