Dual-Supply PA Circuit Using Charge Pump and Envelope Tracking
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Solution Overview
Problem
Current power supply circuits for power amplifiers in radio frequency communication systems are inefficient due to high power consumption and dynamic regulation challenges, particularly in cascaded power amplifier configurations where the output-stage power amplifier consumes the largest current and the driving-stage power amplifier has fixed voltage, leading to inefficiencies and increased costs.
Innovation Solution
A power supply circuit incorporating a charge pump and an envelope tracker dynamically regulates the power supply voltage for the output-stage power amplifier and uses a charge pump with high theoretical efficiency to supply power to the driving-stage power amplifier, along with an average power tracker for varying signal bandwidths to optimize efficiency across different conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single power supply circuit is used for both driving-stage and output-stage power amplifiers, then device complexity is reduced, but power supply efficiency deteriorates due to the large current consumption of the output-stage amplifier
Solution Approach 1:
The power supply circuit is segmented into two independent parts: a first power supply circuit for the driving-stage power amplifier and a second power supply circuit for the output-stage power amplifier. This segmentation allows each circuit to be optimized independently, with the first circuit using a charge pump for high efficiency and the second circuit using an envelope tracker for dynamic regulation, thereby resolving the contradiction between device complexity and power supply efficiency.
2Loss of energy
If an envelope tracker is used to dynamically regulate power supply voltage for the output-stage power amplifier, then power supply efficiency is improved, but device complexity increases
Solution Approach 1:
The envelope tracker is applied locally only to the second power supply circuit for the output-stage power amplifier, which is the component consuming the largest current. This localized application optimizes power efficiency where it is most needed while avoiding unnecessary complexity in the first power supply circuit for the driving-stage amplifier, thus balancing efficiency improvement with complexity management.
3Loss of energy
If a charge pump is used to supply power to the driving-stage power amplifier, then power supply efficiency is improved, but adaptability to varying power demands deteriorates
Solution Approach 1:
The power supply system is segmented such that the charge pump is used in the first power supply circuit for the driving-stage amplifier where high efficiency is prioritized, while the envelope tracker is used in the second power supply circuit for the output-stage amplifier where dynamic regulation capability is prioritized. This segmentation allows each component to operate in its optimal mode without compromising overall system adaptability.
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 solution improves the overall efficiency of the power supply circuit and power amplifier by reducing power consumption and costs, while maintaining flexibility and adaptability to different signal bandwidths, thereby enhancing the performance of the communication apparatus.
Implementation Method 1
The charge pump has a theoretical efficiency of 100% and has a very small actual loss
Implementation Method 2
the power supply voltage of the output-stage power amplifier is dynamically regulable
Data Source
AI summary
In accordance with an embodiment, a power supply circuit configured to be coupled to a power amplifier that includes a driving-stage power amplifier and an output-stage power amplifier. The power amplifier is configured to amplify a power of a radio frequency signal, the driving-stage power amplifier is configured to receive the radio frequency signal, and the output-stage power amplifier is configured to receive a radio frequency signal amplified by the driving-stage power amplifier. The power supply circuit includes: a charge pump configured to supply power to the driving-stage power amplifier; and an envelope tracker configured to supply power to the output-stage power amplifier, wherein the charge pump and the envelope tracker are configured to supply power to the power amplifier.