Envelope Tracking Filter Modeling for RF Power Amplifier Distortion
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Solution Overview
Problem
Power amplifiers in RF communication systems face distortion due to uncontrolled voltage swing caused by loading effects on supply voltage filters, leading to inefficient power consumption and signal distortion.
Innovation Solution
An envelope tracking system with digital modeling circuitry that compensates for distortion by modeling the supply voltage filter, using digital pre-distortion and a multi-level envelope tracker with a DC-to-DC converter to generate regulated voltages and control the power amplifier supply voltage based on envelope signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a supply voltage filter is used to provide stable power to the power amplifier, then power stability is improved, but voltage swing control is worsened due to loading effects
Solution Approach 1:
The system employs feedback mechanisms where the envelope tracker monitors the actual supply voltage to the power amplifier and adjusts the envelope signal accordingly. This closed-loop control compensates for voltage swing distortions caused by filter loading effects, maintaining both power stability and voltage control accuracy simultaneously
Solution Approach 2:
The envelope tracker acts as an intermediary between the power source and the power amplifier. It dynamically adjusts the supply voltage envelope to compensate for distortions introduced by the filter, thereby mediating between the need for stable power delivery and precise voltage swing control
2Manufacturing precision
If digital modeling circuitry is added to compensate for distortion, then signal quality is improved, but system complexity is worsened
Solution Approach 1:
The digital modeling circuitry creates a computational model (copy) of the filter's distortion characteristics. This virtual model allows the system to predict and compensate for distortions without adding physical complexity to the filter itself, improving signal quality through software-based correction
Solution Approach 2:
The system compensates for distortion by dynamically adjusting signal parameters through digital processing. Rather than changing the physical structure of the filter, the approach modifies electrical parameters in the digital domain to counteract the filter's loading effects
Data Source
AI summary
Envelope tracking systems with modeling for power amplifier supply voltage filtering are provided herein. In certain embodiments, an envelope tracking system includes a supply voltage filter, a power amplifier that receives a power amplifier supply voltage through the supply voltage filter, and an envelope tracker that generates the power amplifier supply voltage. The power amplifier provides amplification to a radio frequency (RF) signal that is generated based on digital signal data, and the envelope tracker generates the power amplifier supply voltage based on an envelope signal corresponding to an envelope of the RF signal. The envelope tracking system further includes digital modeling circuitry that models the supply voltage filter and operates to digitally compensate the digital signal data for effects of the supply voltage filter, such as distortion.