Envelope Tracking Power Supply with Linear Voltage Compensation
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Solution Overview
Problem
Modern wireless communication systems using variable envelope modulation technologies face challenges with high Peak-to-Average Power Ratio (PAPR), requiring high linearity and efficiency in power amplifiers, which existing switching power supplies cannot meet due to bandwidth limitations, leading to output noise and distortion affecting Adjacent Channel Power Ratio (ACPR).
Innovation Solution
A tracking power supply system comprising a level providing unit, a level shift unit, a linear amplifier, a current detection unit, and a switch tracking current source, connected in parallel and series to provide high-bandwidth and high-efficiency amplification by compensating the basic voltage and adjusting output current to meet the demands of envelope tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common switching power supply is used for envelope tracking, then the device complexity is reduced, but the bandwidth is insufficient and output noise and distortion increase
Solution Approach 1:
The power supply is segmented into two independent channels: a switching power supply channel for providing basic voltage with high efficiency, and a linear amplifier channel for providing compensation voltage with high bandwidth. This segmentation allows each channel to be optimized for its specific function, resolving the contradiction between device complexity and tracking bandwidth.
Solution Approach 2:
The patent merges the switching power supply and linear amplifier in parallel to form a composite power supply system. The switching power supply provides high-efficiency basic voltage while the linear amplifier provides high-bandwidth compensation voltage, combining the advantages of both technologies to achieve high bandwidth without excessive complexity.
2Speed
If a linear amplifier is used for envelope tracking, then the bandwidth is improved, but the power loss increases and efficiency decreases
Solution Approach 1:
The power supply function is segmented between switching power supply (for efficiency) and linear amplifier (for bandwidth). The switching power supply handles the majority of power delivery with high efficiency, while the linear amplifier only provides small-signal compensation, minimizing its power loss contribution.
Solution Approach 2:
Different parts of the power supply system are assigned different quality characteristics: the switching power supply is optimized for efficiency in handling large power levels, while the linear amplifier is optimized for bandwidth in handling small signal variations. This local optimization resolves the global contradiction between efficiency and bandwidth.
3Loss of energy
If the tracking power supply operates at high efficiency, then the power loss is reduced, but the bandwidth and linearity requirements are not met
Solution Approach 1:
The patent combines switching power supply (high efficiency) and linear amplifier (high linearity and bandwidth) in a parallel configuration. The switching power supply handles bulk power delivery efficiently, while the linear amplifier provides high-fidelity voltage compensation, ensuring both efficiency and linearity requirements are met simultaneously.
Solution Approach 2:
The linear amplifier acts as an intermediary that compensates for the limitations of the switching power supply. It provides the necessary high-bandwidth voltage adjustment that the switching power supply cannot deliver alone, while the switching power supply provides the efficient power delivery that the linear amplifier would be inefficient at providing alone.
Data Source
AI summary
A tracking power supply, a method for controlling a power supply, and a communication apparatus are disclosed. The tracking power supply includes: a basic voltage output unit, configured to provide a basic voltage; and a compensation voltage output unit, configured to provide a compensation voltage. The compensation voltage output unit and the basic voltage output unit are connected in series so as to provide a voltage which is the sum of the basic voltage and the compensation voltage for a load.