Compression-Compensated Power Amplifier for RF Ringing Control

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Solution Overview

Problem

Traditional power amplifiers using N-type devices face issues with voltage and current ringing due to choke coils, leading to large output voltage swings, inefficient device stacking, and reduced efficiency, particularly in MOS-based implementations.

Innovation Solution

A power amplifier system with a main amplifier and a compression compensating (CC) amplifier, utilizing p-type and n-type transistors in series stacks, and AM-AM/AM-PM compensators to improve linearity, especially for 5G applications, maintaining constant input and output capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If N-type devices are used in the output stage to take advantage of higher electron mobility, then power amplification performance is improved, but voltage and current ringing occurs due to the choke coil in the power supply path

Engineering Contradiction:

Improvepower amplification performanceVSAvoidvoltage and current ringing

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

A regulator circuit is introduced as an intermediary component between the power supply and the output stage. This regulator circuit includes a sensing resistor that detects current variations and a control mechanism that adjusts power delivery to counteract the ringing effects caused by the choke coil, thereby maintaining stable power supply to the N-type output stage devices.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If multiple output stage devices are stacked to counter excessive output voltage, then voltage control is improved, but device area and parasitic capacitance increase

Engineering Contradiction:

Improvevoltage controlVSAvoidoutput stage area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent replaces the mechanical stacking of multiple output stage devices with an electrical regulation approach. The regulator circuit dynamically controls the power supply to a single or reduced number of output stage devices, using electrical feedback and control signals to achieve voltage stabilization without requiring additional physical device stacks.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If multiple output stage devices are stacked to handle high impedance levels, then voltage swing control is improved, but efficiency decreases due to multiple capacitive paths

Engineering Contradiction:

Improvevoltage swing controlVSAvoidefficiency loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The regulator circuit employs feedback mechanisms where a sensing resistor monitors current draw and voltage conditions, and this information is fed back to control the power supply adjustment. This closed-loop feedback system enables precise voltage swing control with minimal energy loss, avoiding the efficiency degradation associated with multiple stacked devices and their parasitic capacitances.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12483204B2Power amplifier system

Publication Date: 2025.11.25 QORVO US INC

AI summary

Disclosed is a power amplifier system having a main amplifier with an input coupled to a main radio frequency (RF) input and an output connected to a main RF output, wherein the main amplifier exhibits a nonlinear gain characteristic with compression. At least one compression compensating amplifier has a signal input coupled to the common RF input and a signal output coupled to the common RF output.