Expansion Board Presence Detection Using Passive Connector Pins

Solution Overview

Problem

Existing methods for detecting the presence of expansion boards in electronic systems require active integrated circuits, which increase cost and size, and may fail if these circuits are absent, while connectors conforming to standards like PCIe lack pins for dedicated signals.

Innovation Solution

The use of passive circuits, such as pullup or pulldown resistors, to set multipurpose pins of system connectors to specified states for detecting expansion boards, allowing detection without active integrated circuits and leveraging existing connector pins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If active integrated circuits are used for expansion board detection, then detection reliability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvedetection reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the detection function from active integrated circuits and implements it using passive circuits (pull-up/pull-down resistors) that leverage existing connector pins. This removes the need for additional active components while maintaining detection capability through electrical state sensing of multipurpose pins.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent makes existing multipurpose connector pins serve dual functions: their primary function for data/power transmission and a secondary function for expansion board detection. By configuring these pins as input pins during detection mode, the same physical infrastructure performs both communication and presence detection without requiring dedicated detection pins or circuits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If active integrated circuits are used for expansion board detection, then detection capability is improved, but cost increases

Engineering Contradiction:

Improvedetection capabilityVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive active integrated circuits with inexpensive passive resistive elements (pull-up/pull-down resistors). These passive circuits are significantly cheaper to manufacture and integrate, reducing overall system cost while maintaining sufficient detection capability through electrical state sensing.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent makes existing multipurpose connector pins serve dual functions: their primary function for data/power transmission and a secondary function for expansion board detection. By configuring these pins as input pins during detection mode, the same physical infrastructure performs both communication and presence detection without requiring dedicated detection pins or circuits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If standard PCIe connectors are used, then adapter compatibility is improved, but detection signal capability deteriorates

Engineering Contradiction:

Improveadapter compatibilityVSAvoiddetection signal capability

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent dynamically configures the electrical state of multipurpose pins between different modes: during detection phase, pins are configured as inputs to sense the resistive state indicating board presence; during normal operation, pins switch to their standard output/data transmission functions. This dynamic reconfiguration enables detection capability in standard connectors without permanent structural modifications.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent makes existing multipurpose connector pins serve dual functions: their primary function for data/power transmission and a secondary function for expansion board detection. By configuring these pins as input pins during detection mode, the same physical infrastructure performs both communication and presence detection without requiring dedicated detection pins or circuits.

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 approach reduces costs and simplifies design by eliminating the need for active circuits, while enabling reliable detection of expansion boards and connected components using standard connectors.

Implementation Method 1

The use of passive circuits, such as pullup or pulldown resistors, to set multipurpose pins of system connectors to specified states for detecting expansion boards

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentUS12561188B2Expansion board detection

Publication Date: 2026.02.24 HEWLETT PACKARD ENTERPRISE DEV LP

AI summary

In some examples, a system includes a circuit board having a connector to receive an expansion board. The system includes a controller to detect a state of a signal from the connector and determine a presence or absence of the expansion board in the connector based on the detected state of the signal from the connector. The determining includes indicating the presence of the expansion board in the connector responsive to the signal having a first state as set by a passive circuit on the expansion board through the connector.