Shared Bypass Capacitor Matching Network for RF Amplifiers

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Solution Overview

Problem

In wireless communication systems, the increasing size disparity between active and passive elements on integrated circuits leads to a need for larger board areas for passive components like inductors and capacitors, resulting in higher costs and component redundancy, which can be mitigated by sharing bypass capacitors across multiple amplifiers for impedance matching.

Innovation Solution

A shared bypass capacitor matching network is implemented, where a single capacitor is shared between multiple amplifiers, coupled with shunt inductors and ground, to form an impedance matching network that reduces the number of components required, thereby minimizing board area and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate bypass capacitors are used for each amplifier, then impedance matching is maintained for each amplifier, but the number of components and board area increase

Engineering Contradiction:
Improveimpedance matchingVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple separate bypass capacitors into a single shared bypass capacitor that serves multiple amplifiers simultaneously. This merging approach reduces the total component count while maintaining the impedance matching function for each amplifier through proper circuit configuration and positioning of the shared capacitor at a common reference point.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shared bypass capacitor performs multiple functions by serving as the bypass capacitor for multiple different amplifiers. This multi-functional component design allows a single capacitor to fulfill the impedance matching and signal bypassing needs of several amplifiers, thereby reducing overall component requirements without compromising individual amplifier performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If separate bypass capacitors are used for each amplifier, then each amplifier has dedicated impedance matching, but board area and cost increase

Engineering Contradiction:
Improveimpedance matchingVSAvoidboard area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges multiple separate bypass capacitor placements into a single shared capacitor location on the PCB. This consolidation significantly reduces the board area required for passive components while maintaining effective impedance matching for all amplifiers through the shared component's strategic positioning and electrical connection to a common reference plane.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multiple bypass capacitors are used, then redundancy is provided, but component removal opportunities are lost

Engineering Contradiction:
Improvecomponent redundancyVSAvoidcost reduction
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The shared bypass capacitor is designed to universally serve multiple amplifiers, providing the necessary electrical redundancy and impedance matching functionality that would otherwise require separate capacitors. This universal component approach enables cost reduction by eliminating redundant individual capacitor purchases and assembly operations while maintaining system reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution reduces the number of bypass capacitors needed, resulting in significant cost savings and board area reduction, while maintaining effective impedance matching for radio frequency signals across different bands.

Implementation Method 1

a first capacitor shared between a first matching network for a first amplifier and a second matching network for a second amplifier

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a first inductor coupled to the first amplifier; a second inductor coupled to the second amplifier

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2823569B1Shared bypass capacitor matching network
Publication Date: 2018.09.19 QUALCOMM INC
  • EP2823569B1 patent drawingFigure 1
  • EP2823569B1 patent drawingFigure 2
  • EP2823569B1 patent drawingFigure 3

AI summary

A receiver is described. The receiver includes a first amplifier on an integrated circuit. The receiver also includes a second amplifier on the integrated circuit. The receiver further includes a first inductor coupled to the first amplifier. The receiver also includes a second inductor coupled to the second amplifier. The receiver further includes a first capacitor coupled to the first inductor, the second inductor, and to ground. The first capacitor is shared between a first matching network for the first amplifier and a second matching network for the second amplifier.