VRF Equalizer Circuit for Barely Doherty Load-Modulation Ripple
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Envelope tracking for barely Doherty power amplifiers results in non-linear currents and undesirable ripples due to load modulation, which affects the efficiency and performance of power amplifiers in wireless communication devices.
Innovation Solution
A virtual radio frequency (VRF) equalizer is integrated into the envelope tracking integrated circuit (ETIC) to cancel the ripple caused by load modulation, using circuitry that includes transform functions and additional compensation components to improve the performance and efficiency of the power amplifier stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If envelope tracking is applied to barely Doherty power amplifiers, then efficiency requirements are met, but non-linear currents and undesirable ripples are generated
Solution Approach 1:
The patent applies preliminary anti-action by introducing a ripple cancelation circuit that generates an opposing signal to counteract the ripple produced by load modulation in the barely Doherty power amplifier stage. The circuit proactively creates a cancelation signal before the ripple adversely affects the output, using a transform function to generate the appropriate counter-signal that when combined with the original signal, eliminates the harmful ripple components while preserving the efficiency benefits of envelope tracking
2Use of energy by moving object
If load modulation is used in envelope tracking, then power amplifier efficiency is improved, but non-linear currents are generated
Solution Approach 1:
The patent implements feedback by using a transform function that continuously processes the envelope signal to generate a ripple cancelation signal. The circuit monitors the load modulation effects and dynamically adjusts the cancelation signal to compensate for non-linear current variations, creating a closed-loop system that maintains current linearity while preserving the efficiency improvements from load modulation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A virtual radio frequency (VRF) equalizer for an envelope tracking integrated circuit (ETIC) is disclosed. In one aspect, an ETIC provides envelope tracking (ET) for a barely Doherty (BD) power amplifier stage. The VRF equalizer includes circuitry that provides ripple cancelation that is caused by load modulation of the BD power amplifier stage. Additional circuitry is included to compensate for an amplifier within the ETIC. By canceling the ripple within the ETIC, the overall performance and efficiency of the BD power amplifier stage is improved, resulting in better performance of a transmitter in a wireless communication device.