Cascode RF Power Splitter for Multi-Band Amplification Without Band Switches

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Solution Overview

Problem

Multiband power amplification systems face inefficiencies due to the use of band switches or passive splitters, which introduce loss and require additional semiconductor dies, increasing size, cost, and current drain.

Innovation Solution

A power amplification system utilizing a cascode power amplifier with multiple common base cascode stages that switches between frequency bands without a band switch, sharing a common RF gain path and eliminating the need for additional process technology complexity or semiconductor dies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a band switch is used to switch between frequency bands, then multi-band operation is achieved, but system complexity and cost increase due to additional semiconductor dies

Engineering Contradiction:

Improvemulti-band operationVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the band switching function with the power amplifier stages by integrating multiple cascode stages directly into the amplifier circuit. This eliminates the need for separate band switch components and additional semiconductor dies, thereby achieving multi-band operation while reducing system complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The power amplifier stages are designed to perform dual functions: both amplification and band selection. By making the amplifier stages multi-functional, the patent eliminates the need for dedicated band switching components, reducing overall system complexity while maintaining multi-band capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a passive splitter is used to split RF signals, then signal distribution to multiple filter networks is achieved, but signal loss increases and efficiency decreases

Engineering Contradiction:

Improvesignal distributionVSAvoidsignal loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent converts the potentially harmful signal loss from passive splitting into a benefit by using active power amplifier stages that provide signal gain. The amplification stages compensate for and overcome any inherent signal losses, transforming the disadvantage of signal distribution into an opportunity for signal enhancement across multiple frequency bands

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Adaptability or versatility

If a band switch or passive splitter is used, then frequency band selection or distribution is achieved, but current drain increases due to additional components

Engineering Contradiction:

Improvefrequency band selectionVSAvoidcurrent drain

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent combines band selection and signal amplification into a single integrated circuit architecture. By merging these functions into the power amplifier stages, the patent eliminates the need for separate band switch or splitter components that would consume additional current, thereby reducing overall current drain while maintaining frequency band selection capability

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11316487B2Power splitter with signal amplification

Publication Date: 2022.04.26 SKYWORKS SOLUTIONS INC

AI summary

A power splitter that amplifies an input radio-frequency (RF) signal. The power splitter uses a single transistor in a common emitter stage of a cascode amplifier and two or more common base stages of the cascode amplifier to amplify and to split the input RF signal. A common base biasing signal can be used to simultaneously enable two or more of the common base stages to generate two or more amplified RF output signals.