Envelope Tracking Voltage Windowing for Group Delay Tolerance
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Solution Overview
Problem
Existing power management circuits in 5G-NR mobile communication devices experience amplitude distortion due to group delay, causing misalignment between time-variant voltage and power envelope, which leads to clipping and distortion of RF signals in the mmWave spectrum.
Innovation Solution
A power management circuit with a voltage processing circuit that generates a windowed time-variant target voltage, tolerating group delays by combining first and second group delay circuits to ensure the voltage is higher than or equal to the highest target voltage within defined tolerance windows, thereby avoiding amplitude clipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a power management circuit uses a time-variant voltage to track the power envelope of RF signals, then the operating efficiency of the power amplifier is improved, but group delay causes misalignment between the voltage and power envelope peaks, leading to signal clipping and distortion
Solution Approach 1:
The patent applies preliminary action by detecting the power envelope of the RF signal in advance and generating the time-variant voltage before the signal reaches the power amplifier. The envelope detector captures the signal envelope, and the voltage generator creates the tracking voltage proactively, allowing the system to prepare the appropriate voltage level before the power amplifier processes the RF signal, thus preventing clipping and distortion caused by group delay misalignment
Solution Approach 2:
The patent implements feedback by continuously monitoring the power envelope of the RF signal and using this information to dynamically adjust the time-variant voltage supplied to the power amplifier. The envelope detector provides real-time feedback about the signal characteristics, which is then used by the voltage generator to maintain proper voltage levels, ensuring the power amplifier operates efficiently without causing signal distortion
2Measurement precision
If the power management circuit processes the signal through multiple stages (envelope detection, voltage mapping, voltage generation), then the voltage tracking accuracy is improved, but the processing delay increases, causing greater misalignment with the power envelope
Solution Approach 1:
The patent applies preliminary action by performing envelope detection and voltage generation in advance of the power amplification stage. The envelope detector captures the signal envelope early in the processing chain, and the voltage generator prepares the time-variant voltage before the RF signal reaches the power amplifier, compensating for the inherent processing delay through proactive voltage establishment
Solution Approach 2:
The patent segments the power management circuit into distinct functional blocks: an envelope detector that separates the power envelope from the RF signal, a voltage generator that converts the envelope to a time-variant voltage, and a lookup table that maps envelope values to target voltages. This segmentation allows each stage to be optimized independently, maintaining tracking accuracy while managing processing delay through parallel processing paths
Data Source
AI summary
A power management circuit operable with group delay is provided. In embodiments disclosed herein, the power management circuit includes a voltage processing circuit configured to receive a first time-variant target voltage having a first group delay relative to a time-variant target voltage and a second time-variant target voltage having a second group delay relative to the time-variant target voltage. Accordingly, the voltage processing circuit generates a windowed time-variant target voltage higher than or equal to a highest one of the first time-variant target voltage and the second time-variant target voltage in a group delay tolerance window(s) defined by the first group delay and the second group delay. As a result, the power management circuit can generate a time-variant voltage based on the windowed time-variant target voltage to help a power amplifier to avoid amplitude clipping when amplifying an analog signal.