Envelope Tracking RF Front-End Circuit for Low-Distortion PA Supply
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Solution Overview
Problem
Conventional envelope tracking (ET) RF front-end circuits in 5G-NR mobile communication devices suffer from distortion in time-variant power envelopes due to long conductive traces between the baseband transceiver and the RF front-end module, leading to reduced efficiency and performance of power amplifiers, especially at higher modulation bandwidths.
Innovation Solution
A self-contained ET RF front-end circuit is designed with an integrated circuit (ETIC), a local transceiver circuit, and a target voltage circuit to generate time-variant ET voltages within the circuit, reducing distortion and improving power amplifier efficiency by minimizing the distance-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the baseband transceiver is located far from the RF front-end module, then the device layout is flexible, but the conductive trace length increases causing distortion in the time-variant power envelope
Solution Approach 1:
The patent combines the target voltage circuit and ETIC into an integrated ET RF front-end circuit that is co-packaged with the power amplifiers. This merging eliminates the need for long external conductive traces, as the time-variant power envelope is generated internally within the same package, thereby preventing distortion while maintaining layout flexibility.
Solution Approach 2:
The patent introduces an on-package trace as an intermediary conductive path between the target voltage circuit and the power amplifiers. This short on-package trace acts as a mediator that preserves the integrity of the time-variant power envelope signal by minimizing exposure to distortion-causing factors present in longer external traces.
2Device complexity
If conventional ET RF front-end circuits are used with long conductive traces, then device integration is simpler, but power amplifier efficiency decreases due to signal distortion
Solution Approach 1:
The patent merges the target voltage circuit, ETIC, and power amplifiers into a single co-packaged ET RF front-end circuit. This integration maintains relative simplicity while dramatically improving power amplifier efficiency by eliminating the power envelope distortion that occurs over long external conductive traces.
3Loss of energy
If the conductive trace length is reduced, then power amplifier efficiency is improved, but device layout flexibility is reduced
Solution Approach 1:
By co-packaging the ET RF front-end circuit with the power amplifiers in the same module, the patent achieves both short trace lengths for high efficiency and flexible device layout. The integration allows the entire ET system to be positioned optimally within the device without being constrained by long external trace requirements.
Data Source
AI summary
An envelope tracking (ET) radio frequency (RF) front-end circuit is provided. The ET RF front-end circuit includes an ET integrated circuit(s) (ETIC(s)), a local transceiver circuit, a target voltage circuit(s), and a number of power amplifiers. The local transceiver circuit receives an input signal(s) from a coupled baseband transceiver and generates a number of RF signals. The target voltage circuit(s) generates a time-variant ET target voltage(s) based on the input signal(s). The ETIC(s) generates multiple ET voltages based on the time-variant ET target voltage(s). The power amplifiers amplify the RF signals based on the ET voltages. Given that the time-variant ET target voltage(s) is generated inside the self-contained ET RF front-end circuit, it is possible to reduce distortion in the time-variant ET target voltage(s), thus helping to improve operating efficiency of the power amplifiers, especially when the RF signals are modulated with a higher modulation bandwidth (e.g., ≥200 MHz).