Digital Envelope Tracking Modulator With Dynamic Switched-Capacitor Levels
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Solution Overview
Problem
Existing digital envelope tracking techniques face limitations in achieving optimal power efficiency due to fixed voltage levels and power losses from charging or discharging, which hinder the overall performance of power amplifiers in RF systems.
Innovation Solution
A digital envelope tracking supply modulator comprising a switching converter, a dynamic switched-capacitor circuit, and a digital control circuit, which dynamically generates multiple supplement voltages to optimize the output envelope tracking voltage, utilizing a quasi-DC converter for DC levels and a fast supplementary AC source to enhance power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a voltage divider with fixed voltage levels is used for digital envelope tracking, then the circuit complexity is reduced, but power efficiency deteriorates due to power loss from charging or discharging
Solution Approach 1:
The patent applies dynamics by making the number of voltage levels variable rather than fixed. The switched-capacitor circuit dynamically adjusts the number of DET levels based on operating conditions, allowing the system to optimize between complexity and power loss by selecting appropriate voltage level configurations in real-time
Solution Approach 2:
The patent changes the parameter of voltage levels from fixed to variable. By dynamically adjusting the number of voltage levels and switching frequency based on pre-calculated power-added efficiency and converter loss, the system optimizes power efficiency while managing circuit complexity
2Reliability
If analog envelope tracking techniques are used, then power amplifier performance is optimized, but power consumption increases due to linear amplifiers
Solution Approach 1:
The patent substitutes analog/mechanical envelope tracking techniques with a digital approach. By using digital control circuits to generate control signals for switched-capacitor cells, the system replaces power-consuming linear amplifiers with a digital control architecture, reducing power consumption while maintaining power amplifier performance
Solution Approach 2:
The patent changes the operating state by dynamically adjusting the number of voltage levels and switching frequency. This allows the system to optimize the balance between power amplifier performance and power consumption by selecting appropriate operating parameters based on pre-calculated efficiency data
3Loss of energy
If the number of DET levels is increased to improve power efficiency, then power loss from charging or discharging is reduced, but device complexity increases
Solution Approach 1:
The patent applies dynamics by making the number of DET levels adjustable rather than fixed. The system dynamically selects the optimal number of voltage levels based on operating conditions, allowing it to reduce power loss when needed while avoiding unnecessary complexity by using only the required number of levels for each operating state
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
The solution achieves improved power efficiency by dynamically adjusting the number of DET levels and switching frequency based on pre-calculated power-added efficiency and converter loss, optimizing the power amplifier's performance while minimizing energy wastage.
Implementation Method 1
the switching converter is configured to convert an input supply voltage into an output envelope tracking (ET) voltage according to a first control signal
Implementation Method 2
The dynamic switched-capacitor circuit is configured to output multiple supplement voltages for supplementing alternating current (AC) components of the output ET voltage by multiple stages
Data Source
AI summary
A digital envelope tracking (DET) supply modulator is provided. The DET supply modulator includes a switching converter, a dynamic switched-capacitor circuit and a digital control circuit. The switching converter converts an input supply voltage into an output envelope tracking (ET) voltage according to a first control signal. The dynamic switched-capacitor circuit outputs multiple supplement voltages for supplementing alternating current (AC) components of the output ET voltage by multiple stages. More particularly, the dynamic switched-capacitor circuit comprises multiple switched-capacitor cells and a selection circuit, wherein the selection circuit is coupled to the multiple switched-capacitor cells. In detail, the multiple switched-capacitor cells generate the multiple supplement voltages, respectively, and the selection circuit controls switching of each of the multiple switched-capacitor cells according to a second control signal. The digital control circuit generates the first control signal and the second control signal according to a target envelope waveform of the output ET voltage.