Differential RF Amplifier Switching Without Baluns

Solution Overview

Problem

Existing amplifiers with RF switch functions face challenges in size reduction and noise characteristics due to the need for elements like baluns for differential signal handling, leading to increased size and deteriorated noise performance.

Innovation Solution

A differential amplifier with an RF switch function that includes N differential amplification circuits connected in parallel, allowing differential signal output without baluns, and a sequence circuit for selective driving and power-down control of these circuits to reduce size and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If balun elements are used for conversion between balanced and unbalanced circuits, then differential signal handling is enabled, but circuit size increases and noise characteristics deteriorate

Engineering Contradiction:

Improvedifferential signal handling capabilityVSAvoidcircuit size

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

The invention extracts and eliminates the balun conversion elements from the circuit configuration. By using a differential amplifier with differential input and output terminals directly, the patent removes the need for separate balun components that perform balanced-to-unbalanced conversion, thereby reducing circuit size while maintaining differential signal handling capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The differential amplifier circuit is designed to perform multiple functions: it provides differential signal amplification, maintains differential signal output capability, and eliminates the need for separate balun components. This multi-functionality allows the circuit to handle differential signals directly without requiring additional conversion elements

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If balun elements are used for conversion between balanced and unbalanced circuits, then differential signal handling is enabled, but noise characteristics deteriorate

Engineering Contradiction:

Improvedifferential signal handling capabilityVSAvoidnoise characteristics

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and eliminates the balun conversion elements from the circuit configuration. By using a differential amplifier with differential input and output terminals directly, the patent removes the need for separate balun components that perform balanced-to-unbalanced conversion, thereby reducing circuit size while maintaining differential signal handling capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The differential amplifier circuit is designed to perform multiple functions: it provides differential signal amplification, maintains differential signal output capability, and eliminates the need for separate balun components. This multi-functionality allows the circuit to handle differential signals directly without requiring additional conversion elements

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple differential amplification circuits are connected in parallel, then RF switch function is implemented, but circuit complexity increases

Engineering Contradiction:

ImproveRF switch functionVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention merges multiple differential amplification circuits into a single integrated differential amplifier structure. By connecting multiple amplification circuits in parallel with a common input terminal and multiple output terminals, the patent achieves RF switch functionality while reducing overall circuit complexity compared to using separate amplifiers with conversion elements

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The differential amplifier circuit is designed to perform multiple functions: it provides differential signal amplification, maintains differential signal output capability, and eliminates the need for separate balun components. This multi-functionality allows the circuit to handle differential signals directly without requiring additional conversion elements

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4576570A1Amplifier with differential RF switch function

Publication Date: 2025.06.25 FUJIKURA LTD

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AI summary

A differential amplifier with an RF switch function includes an input matching circuit, N (N is an integer of 2 or more) differential amplification circuits connected to the input matching circuit, and N output matching circuits connected to the N differential amplification circuits in a one-to-one manner. The N differential amplification circuits are connected in parallel. Only one of the N differential amplification circuits is driven.