H-Bridge Power Amplifier Envelope Tracking Current Recycling

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Solution Overview

Problem

Current power amplifier systems face inefficiencies and linearity issues, particularly with high peak-to-average-power ratio (PAPR) signals in advanced wireless communication systems, which are exacerbated by the need for stringent linearity and broadband performance in 5G and beyond technologies.

Innovation Solution

The H-bridge power amplifier arrangement integrates envelope tracking and sinking current recycling, utilizing a novel H-bridge structure with dual and triple supply rails to generate sourcing and sinking envelope currents, and a rectifier circuit to recycle redundant sinking current power, enhancing efficiency and linearity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If traditional PA architectures are used in wideband applications, then the circuit implementation is simple, but the power efficiency is rather low

Engineering Contradiction:
Improvepower efficiencyVSAvoidcircuit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The power amplifier is segmented into multiple functional blocks: a first PA block and a second PA block, each handling different signal components. The envelope signal is also segmented and applied differently to each block, allowing independent optimization of each segment for overall system efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The power supply voltage to the first PA block is dynamically adjusted according to the envelope signal, enabling the amplifier to operate at peak efficiency across varying output power levels. The supply voltage varies in real-time to match the signal envelope, optimizing efficiency dynamically

Inventive Principle:
Principle #15Dynamics

2Reliability

If linear power amplifiers (classes A, AB and B) are used to meet noise requirements, then linearity is improved, but power efficiency decreases

Engineering Contradiction:
ImprovelinearityVSAvoidpower efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention merges linear and switch-mode amplifier topologies into a hybrid architecture. The first PA block operates in linear mode for linearity-critical signals, while the second PA block handles other components, combining the advantages of both approaches to achieve both linearity and efficiency

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The operating parameters of the power amplifiers are dynamically changed by adjusting the supply voltage according to the envelope signal. This allows the amplifiers to transition between different operating regions, maintaining linearity when needed while improving efficiency through parameter optimization

Inventive Principle:
Principle #35Parameter changes

3Productivity

If high PAPR signals are transmitted to achieve high data throughput, then data rate is improved, but average efficiency deteriorates due to significant backoff from peak power

Engineering Contradiction:
Improvedata throughputVSAvoidaverage efficiency
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The power supply voltage is dynamically adjusted to track the envelope of the high PAPR signal, allowing the amplifier to operate efficiently across the full dynamic range from peak to average power levels. This eliminates the need for conservative backoff and maintains high efficiency even with high data throughput requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The envelope tracking mechanism provides feedback control where the power supply voltage is continuously adjusted based on the instantaneous envelope of the output signal. This feedback loop ensures the amplifier operates at optimal efficiency points regardless of the signal's PAPR characteristics

Inventive Principle:
Principle #23Feedback

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 improves the efficiency and linearity of power amplifiers, enables easy transformation between envelope tracking and average power tracking modes, and recycles sinking power to boost overall system efficiency.

Implementation Method 1

a rectifier circuit to recycle the sinking envelope current by converting a redundant sinking current power to a direct current (DC) voltage

Methodology Applied
Scientific EffectRectification: Diode

Data Source

PatentEP3750239B1H-bridge power amplifier arrangement
Publication Date: 2022.05.04 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3750239B1 patent drawingFigure 1
  • EP3750239B1 patent drawingFigure 2
  • EP3750239B1 patent drawingFigure 3(a)~3(b)

AI summary

An H-bridge power amplifier arrangement (100) with envelope tracking is disclosed. The power amplifier arrangement (100) comprises four elements (A, B, C, D) form the four corner bars of a first H-bridge structure with a load (103) formed as thecross bar of the first H-bridge structure. The power amplifier arrangement (100) further comprises a rectifier circuit (104) coupled between the first positive power supply (V H) and the third positive power supply (V L) configured to recycle the sinking envelope current.