Power Amplifier Supply Control Using Calibrated Envelope Tracking
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Solution Overview
Problem
Traditional dynamic supply control schemes for power amplifiers, such as envelope tracking, are limited by bandwidth constraints, leading to inefficiencies in high-frequency applications like modern wireless communication systems, where the existing hybrid solutions with DC/DC converters and fast linear regulators are complex and inefficient.
Innovation Solution
An apparatus and method that implement a time domain open loop envelope tracking compensation using a fast switching DC/DC converter with a calibration feedback loop, allowing for bandwidth expansion without the need for a linear regulator, and an adaptive calibration loop to compensate for power amplifier load variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional dynamic supply control schemes (envelope tracking) are used for power amplifiers, then efficiency is improved, but bandwidth is limited to narrow-bandwidth applications of few MHz
Solution Approach 1:
The supply control system is segmented into two independent parts: a DC/DC converter for efficiency and a fast linear regulator for bandwidth. This segmentation allows each component to optimize for its specific function, resolving the contradiction between efficiency and bandwidth by distributing these requirements to different system segments.
Solution Approach 2:
A fast linear regulator is introduced as an intermediary component between the DC/DC converter and the power amplifier. This intermediary handles the high-frequency supply variations that the DC/DC converter cannot respond to quickly enough, thereby extending the effective bandwidth while maintaining the efficiency benefits of envelope tracking.
2Speed
If hybrid envelope tracking solutions with DC/DC converter and fast linear regulator are implemented, then bandwidth is improved, but system complexity increases
Solution Approach 1:
The patent merges the DC/DC converter and fast linear regulator into a coordinated hybrid system where both components work together under unified control. This combining approach achieves extended bandwidth while managing complexity through integrated control architecture rather than separate independent systems.
Solution Approach 2:
The system dynamically switches between the DC/DC converter and fast linear regulator based on the frequency content and power requirements. This dynamic operation allows the system to use the efficient DC/DC converter for low-frequency variations and the faster linear regulator only when high-frequency response is needed, reducing overall system complexity.
3Speed
If hybrid envelope tracking solutions with DC/DC converter and fast linear regulator are implemented, then bandwidth is improved, but efficiency is reduced
Solution Approach 1:
The fast linear regulator operates partially, only when and where needed to supplement the DC/DC converter's response. By using the linear regulator only for the specific high-frequency components that the DC/DC converter cannot handle, the system achieves bandwidth extension with minimal efficiency loss from the less-efficient linear regulation.
Solution Approach 2:
The DC/DC converter maintains continuous efficient operation for the bulk of the power supply requirements, while the fast linear regulator provides continuous but partial supplementation only when high-frequency response is needed. This continuous coordinated action ensures efficiency is maintained wherever possible while bandwidth is extended where required.
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
This approach significantly enhances the efficiency of power amplifiers, achieving up to 90% efficiency for LTE 20 and LTE 40, and over 85% for WiFi 80, while maintaining high bandwidth, thus addressing the limitations of conventional hybrid envelope tracking solutions.
Implementation Method 1
a fast switching DC/DC converter with a calibration feedback loop
Implementation Method 2
an adaptive calibration loop to compensate for power amplifier load variations
Data Source
AI summary
An apparatus for providing a supply control signal for a supply unit, the supply unit being configured to provide a variable controlled power supply to the power amplifier. The apparatus includes a determination module configured to determine a deviation of a signal from at least one nominal value; and an adjustment module configured to provide the supply control signal after an adjustment based on the determined deviation.