Inverted Group Delay Circuit for RF Envelope Timing Alignment
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Solution Overview
Problem
In 5G-NR mobile communication devices, the inherent processing delay in power management circuits leads to misalignment between time-variant voltage and RF signal envelopes, causing amplitude distortion in RF signals amplified by power amplifiers.
Innovation Solution
An inverted group delay circuit, comprising a tunable RC circuit and operational amplifier, is introduced to offset group delays between time-variant voltage and envelope signals, ensuring better alignment and reducing amplitude distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a power management circuit is used to generate time-variant voltage by detecting and mapping the power envelope, then the operating efficiency of the power amplifier is improved, but the inherent processing delay causes misalignment between the time-variant voltage and the RF signal envelope
Solution Approach 1:
The patent applies preliminary action by introducing an inverted group delay circuit that pre-compensates for the processing delay. The circuit generates an inverted time-variant voltage with opposing phase and time-adjusted characteristics before the delay occurs, so that when the delayed voltage is applied to the power amplifier, it aligns properly with the RF signal envelope peaks, preventing clipping and distortion
2Ease of operation
If the time-variant voltage is generated with processing delay, then the power management function is achieved, but the peaks of the time-variant voltage become misaligned with the peaks of the time-variant power envelope causing signal clipping
Solution Approach 1:
The patent applies inversion by using an inverting operational amplifier to generate a time-variant voltage with opposing phase. This inverted voltage is then fed through a tunable RC circuit that provides group delay compensation. The inversion allows the circuit to counteract the timing misalignment by producing a voltage that, when delayed, will peak at the correct time to match the RF envelope
3Power
If the power amplifier amplifies the RF signal based on delayed time-variant voltage, then the amplification function is performed, but amplitude distortion occurs due to the misalignment between voltage and envelope
Solution Approach 1:
The patent applies feedback by using a tunable RC circuit with feedback mechanism that adjusts the group delay of the inverted time-variant voltage. The feedback allows the circuit to optimize the timing alignment between the control voltage and the RF signal envelope, ensuring that the power amplifier operates with high signal fidelity and minimal amplitude distortion while maintaining full amplification capability
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
The inverted group delay circuit improves timing alignment between voltage and envelope signals, thereby reducing amplitude distortion and enhancing the operating efficiency of power amplifiers in 5G-NR devices.
Implementation Method 1
The operational amplifier also includes an output terminal configured to output an inverted time-variant voltage having an opposing phase and time-adjusted relative to the time-variant voltage
Implementation Method 2
The tunable RC circuit is configured to output a time-variant voltage having a group delay relative to a time-variant envelope of an analog signal
Data Source
AI summary
An inverted group delay circuit is provided. The inverted group delay circuit can offset a group delay between a pair of signals. In a non-limiting example, the inverted group delay circuit can be configured to offset a group delay (e.g., negative group delay) between a time-variant voltage and a time-variant envelope of an analog signal. More specifically, the inverted group delay circuit can output an inverted time-variant voltage having an opposing phase and time-adjusted relative to the time-variant voltage to thereby offset the group delay between the time-variant voltage and the time-variant envelope. As such, the inverted group delay circuit can be provided in a power management integrated circuit (PMIC) to improve timing alignment between a time-variant voltage(s) and a time-variant analog signal(s) at a power amplifier(s), thus helping to reduce potential amplitude distortion when the analog signal(s) is amplified by the power amplifier(s).