PMIC Group Delay Detection for RF Power Amplifier Timing Alignment
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Solution Overview
Problem
In 5G-NR mobile communication devices, the misalignment between modulated voltage and modulated current at the power amplifier due to different group delays leads to degraded error vector magnitude (EVM) and adjacent channel leakage ratio (ACLR) in RF signals, which is challenging to measure and correct, especially when using multiple power amplifier circuits from different vendors.
Innovation Solution
A group delay determination circuit within the PMIC that estimates the relative group delay between the modulated voltage and current based on known signals, allowing for time alignment and enabling delay adjustments to improve EVM and ACLR, without requiring complex calibration equipment or knowledge of the power amplifier circuit's internal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power amplifier circuit amplifies the RF signal based on modulated voltage and modulated current from different sources, then the amplification capability is improved, but the group delay misalignment between voltage and current degrades the EVM and ACLR performance
Solution Approach 1:
The patent implements a feedback mechanism where the group delay determination circuit continuously measures the relative group delay between modulated voltage and modulated current, and the transceiver circuit adjusts the timing of modulated voltage based on this feedback to compensate for the delay misalignment, thereby improving EVM and ACLR performance while maintaining amplification capability
Solution Approach 2:
The patent changes the timing parameter of modulated voltage dynamically by adjusting its phase or time of arrival at the power amplifier circuit based on the measured relative group delay, which compensates for the delay mismatch and improves signal quality metrics (EVM and ACLR) without sacrificing power amplification capability
2Measurement precision
If complex calibration equipment and knowledge of power amplifier circuit internal operations are used to measure and correct group delay, then measurement precision is improved, but device complexity and ease of manufacture deteriorate
Solution Approach 1:
The patent implements a self-service approach where the power management integrated circuit itself performs the group delay measurement and correction functions using internally available signals (modulated voltage and modulated current), eliminating the need for external calibration equipment and specialized knowledge of power amplifier internal operations, thus maintaining measurement precision while reducing device complexity
Solution Approach 2:
The power management integrated circuit is designed to perform multiple functions including both power management and group delay determination, allowing it to use its existing signal paths and processing capabilities to measure and correct group delay without requiring separate dedicated calibration equipment, thereby improving measurement precision while simplifying the overall system
Data Source
Figure 1A
Figure 1B~1C
Figure 2
AI summary
Group delay determination in a communication circuit is disclosed. The communication circuit includes a power amplifier circuit that amplifies a radio frequency (RF) signal based on a modulated voltage and a power management integrated circuit (PMIC) that generates the modulated voltage. Herein, the PMIC includes a group delay determination circuit to determine a relative group delay between the modulated voltage and a modulated current, which is internal to the power amplifier circuit and unknown to the PMIC, solely based on signals known to the PMIC. The determined relative group delay can help to time align the modulated voltage with the modulated current at the power amplifier circuit to improve error vector magnitude (EVM) and/or adjacent channel leakage ratio (ACLR). Further, by determining the relative group delay based on known signals to the PMIC, it is possible to achieve good time alignment between the modulated voltage and the modulated current.