Hybrid Voltage Modulator for RF Envelope Tracking
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Solution Overview
Problem
Existing voltage modulators face challenges in achieving high bandwidth and high efficiency simultaneously, particularly in envelope tracking for RF power amplifiers, due to switching losses in switched voltage regulators and poor efficiency of linear modulators.
Innovation Solution
A voltage modulator configuration combining a multi-level switched capacitor modulator with a switched voltage regulator, controlled by dual loops to manage voltage storage and output tracking, allowing for non-overlapping switching and adaptive operation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If switched voltage regulators are used to achieve high bandwidth, then switching speed increases, but switching losses increase due to frequent switching
Solution Approach 1:
The patent divides the voltage modulation function into two separate modules: a switched voltage regulator for high-efficiency bulk power conversion and a switched capacitor modulator for high-bandwidth envelope tracking. This segmentation allows each module to operate in its optimal efficiency region, resolving the contradiction between bandwidth and switching losses.
Solution Approach 2:
The switched capacitor modulator uses periodic switching at a fixed frequency to generate the high-frequency voltage swings needed for envelope tracking. This periodic action provides the necessary bandwidth without requiring the main voltage regulator to switch frequently, thereby reducing switching losses.
2Speed
If linear modulators are used to achieve high bandwidth, then response speed increases, but efficiency deteriorates due to poor power conversion
Solution Approach 1:
The patent merges a switched voltage regulator and a switched capacitor modulator into a hybrid architecture. The regulator handles the bulk power conversion with high efficiency, while the capacitor modulator adds the necessary bandwidth through capacitive switching. This combination achieves both high efficiency and high bandwidth, overcoming the limitations of linear modulators.
3Loss of energy
If multi-level supply modulators are used to reduce switching losses, then efficiency improves, but device complexity increases due to multiple levels
Solution Approach 1:
The switched capacitor modulator acts as an intermediary between the bulk power regulator and the RF power amplifier. It uses a simple two-level capacitor switching architecture to provide the necessary voltage modulation, avoiding the complexity of multi-level modulators while maintaining high efficiency through reduced switching losses.
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 configuration enhances efficiency and bandwidth, reducing switching losses and enabling efficient tracking of input signals with improved power management, as demonstrated by simulation results showing high power efficiency and reduced output voltage ripple.
Implementation Method 1
The multi-level switched capacitor modulator may comprise a multi-level charge pump
Data Source
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AI summary
A voltage modulator (400) comprises a multi-level switched capacitor modulator (44) connected in parallel with a switched voltage regulator (42). An output of the multi-level switched capacitor modulator and an output of the switched voltage regulator are combined, or both connected to an output node, to generate an output voltage. The voltage modulator has an input node to receive at least one input signal and further comprises a control unit (46) arranged to control the switched voltage regulator and the multi-level switched capacitor modulator such that the output voltage follows the input signal.