Envelope Tracking Circuit With FSPT for Bandwidth Matching
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Solution Overview
Problem
Traditional envelope tracking methods result in a bandwidth of the envelope signal being more than twice that of the input signal, leading to inefficiencies and signal distortion due to differences in transmission paths, particularly when the input signal's bandwidth is broad, causing time misalignments and energy inefficiencies.
Innovation Solution
The implementation of a Fine Slot Peak Tracking (FSPT) circuit within an envelope tracking device that adjusts the bandwidth of the envelope signals by sampling, calculating, extracting, expanding, smoothing, and filtering the input signals to generate envelope signals with a controlled bandwidth, thereby reducing energy consumption and improving signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional envelope tracking methods are used, then the envelope signal can be generated, but the bandwidth of the envelope signal becomes more than twice that of the input signal, causing energy inefficiency
Solution Approach 1:
The patent changes the bandwidth parameter of the envelope signal from being proportional to (or more than twice) the input signal bandwidth to being substantially equal to the input signal bandwidth. This is achieved through the FSPT circuit that processes the input signal through sampling, peak detection, pulse generation, and filtering stages to control the envelope signal bandwidth parameter.
2Productivity
If the bandwidth of the input signal is broad, then more information can be transmitted, but the bandwidth of the envelope signal needs to be wider, causing loss of efficiency
Solution Approach 1:
The patent establishes a direct relationship between input signal bandwidth and envelope signal bandwidth, where the envelope signal bandwidth is controlled to be substantially equal to the input signal bandwidth rather than exceeding it. The FSPT circuit maintains this parameter relationship across different bandwidth conditions, ensuring efficiency is preserved regardless of transmission capacity requirements.
3Reliability
If different transmission paths are used for input signal and envelope signal, then signal processing can be independent, but time misalignments occur leading to signal distortion
Solution Approach 1:
The patent merges the input signal processing and envelope signal generation into a single integrated FSPT circuit path. The input signal passes through sampling, peak detection, pulse generation, and filtering stages that simultaneously produce both the processed input signal and the corresponding envelope signal, ensuring they remain time-aligned while maintaining processing independence through the circuit's modular stages.
Data Source
AI summary
An envelope tracking device includes a fine slot peak tracking (FSPT) circuit, at least one power amplifier, and an envelope modulator. The FSPT circuit is connected to the power amplifier through the envelope modulator. The FSPT circuit generates envelope signals based on input signals, adds an offset to the envelope signals, and expands and smoothes the added envelope signals. The envelope modulator generates envelope voltage signals according to the smoothed envelope signals, and outputs the signals to drain of the power amplifier. The envelope voltage signals are time-aligned with the amplified signals which are transmitted to gate of the power amplifier.