Hybrid Power Supply for Ultrafast RF Amplifier Modulation
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Solution Overview
Problem
Radio frequency (RF) linear power amplifiers face efficiency reduction due to slow modulation of supply voltage, leading to increased energy consumption, component oversizing, and noise in communication channels, as traditional DC-DC converters are unable to achieve the required ultrafast modulation rates.
Innovation Solution
A circuit comprising an amplitude correction circuit and an open-loop switching regulator, along with a summing circuit that generates a corrected envelope signal to power the power amplifier, allowing for fast modulation of the supply voltage to match the dynamic requirements of RF signals, and a hybrid configuration of switching and linear regulators to ensure efficient power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional PWM DC-DC converters are used to power RF power amplifiers, then the power supply can maintain a constant output voltage, but the modulation rate is limited to two to three orders of magnitude below the required ultrafast modulation rates
Solution Approach 1:
The power supply is divided into two separate regulator channels: a first regulator (switching regulator) that provides the bulk power at high efficiency, and a second regulator (linear regulator) that provides fast modulation capability. This segmentation allows each regulator to optimize for its specific function, resolving the contradiction between high efficiency and fast modulation rate.
Solution Approach 2:
The patent combines two different regulator architectures (switching and linear) into a single hybrid power supply system that serves one load. The switching regulator handles the constant voltage component while the linear regulator handles the time-varying envelope component, merging their advantages to achieve both high efficiency and ultrafast modulation.
2Stability of the object's composition
If the supply voltage is kept constant to maintain power amplifier operating point, then stability is improved, but efficiency is severely reduced when RF signal envelope is lower than maximum
Solution Approach 1:
The power supply transitions from a static constant voltage output to a dynamic output that follows the RF signal envelope in real-time. The second regulator dynamically adjusts the voltage to match the instantaneous amplitude requirements, allowing the first regulator to maintain stability while the second provides the necessary dynamic adaptation for efficiency.
3Device complexity
If traditional regulators are used, then the circuit design is simpler, but distortion and noise emerge due to insufficient bandwidth
Solution Approach 1:
The regulation function is segmented into two frequency domains: the first regulator handles the low-frequency DC component, and the second regulator handles the high-frequency envelope variations. This segmentation allows each regulator to operate within its optimal bandwidth, eliminating the distortion and noise that would result from using a single regulator with insufficient bandwidth.
Data Source
AI summary
A circuit for use with a power amplifier that amplifies an input signal. The circuit may comprise an amplitude correction circuit and an open-loop switching regulator. The amplitude correction circuit may be configured to generate a corrected envelope signal from an input envelope signal that represents an envelope of the input signal. The open-loop switching regulator may be connected to the amplitude correction circuit and may be for powering the power amplifier based on the corrected envelope signal. According to various embodiments, the corrected envelope signal generated by the amplitude correction circuit is a function of the input envelope signal and an error voltage of the open-loop switching regulator.