Envelope Tracking Circuit Phase Correction for RF Power Amplifiers
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Solution Overview
Problem
The inherent processing delay in envelope tracking integrated circuits (ETICs) causes misalignment between the time-variant ET voltage and the time-variant power envelope of RF signals, leading to clipping and distortion in power amplifiers used in 5G-NR mobile communication devices operating in the mmWave RF spectrum.
Innovation Solution
A power management circuit with an ETIC that generates a modulated voltage and phase correction voltage based on the time-variant power envelope, ensuring good time and phase alignment through correlation between the modulated voltage, phase correction voltage, and power envelope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope tracking is used to improve power amplifier efficiency, then operating efficiency is improved, but processing delay causes phase misalignment between ET voltage and power envelope
Solution Approach 1:
The patent applies preliminary action by predicting future power envelope values based on historical data and current state, allowing the ET voltage to be prepared in advance to compensate for processing delays. The prediction mechanism calculates anticipated power levels before they occur, enabling the power amplifier to maintain proper phase alignment without waiting for real-time feedback.
Solution Approach 2:
The patent implements feedback by continuously monitoring actual power envelope values and comparing them with predicted values, then using this information to refine future predictions. The feedback loop adjusts the prediction algorithm based on the difference between expected and actual power levels, improving accuracy over time and maintaining synchronization despite varying signal conditions.
2Reliability
If processing delay is reduced to improve phase alignment, then time and phase alignment is improved, but this may compromise other ETIC functions
Solution Approach 1:
By performing predictions in advance based on stored historical data, the system achieves phase alignment without requiring complex real-time processing. The preliminary calculation of future power levels allows the ETIC to maintain simplicity while achieving high reliability in phase alignment.
Solution Approach 2:
The prediction mechanism uses the ETIC's own historical data and current state to generate predictions, eliminating the need for external complex processing systems. The ETIC serves itself by leveraging its internal memory and processing capabilities to maintain phase alignment independently.
3Manufacturing precision
If correlation-based generation is used to improve voltage alignment, then efficiency and linearity are improved, but computational complexity increases
Solution Approach 1:
The patent changes the approach from complex continuous optimization to discrete parameter-based prediction. By using historical power envelope values and current state parameters to predict future values, the system achieves precise voltage alignment through simpler parameter manipulation rather than complex computational optimization.
Solution Approach 2:
The prediction mechanism creates a simplified model or copy of the power envelope behavior based on historical patterns. This copied model allows the ETIC to generate appropriate ET voltage without performing complex real-time calculations, reducing computational complexity while maintaining alignment precision.
Data Source
AI summary
A power management circuit supporting phase correction in an analog signal is disclosed. The power management circuit includes a power amplifier circuit configured to amplify an analog signal having a time-variant power envelope based on a modulated voltage. The power management circuit also includes an envelope tracking (ET) integrated circuit (ETIC) configured to generate the modulated voltage and a modulated phase correction voltage to thereby cause a phase change in the analog signal. In embodiments disclosed herein, a correlation between the time-variant power envelope, the modulated voltage, and the modulated phase correction voltage is explored to thereby allow the ETIC to generate the modulated voltage and the modulated phase correction voltage based on the time-variant power envelope. As a result, it is possible to enable good time and phase alignment between the modulated voltage and the time-variant power envelope to thereby improve efficiency and linearity of the power amplifier circuit.