Hot Swap Controller Dual-Path Current Limiting

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Solution Overview

Problem

In-rush currents caused by capacitive components when an electrical load is connected to a live power source can perturb the operation of the source and other loads, triggering protective measures and potentially affecting the power supply and connected circuits, especially if the new load is faulty.

Innovation Solution

A controller device with a power converter circuit and electronic switches that manage current flow through two paths to limit in-rush currents by controlling the operation of the power converter circuit and electronic switches, providing a first current in a first path during a first time period and a second current in a second path after the first time period begins, ensuring safe and controlled charging of the load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a load is connected to a live power source, then the load can be powered up immediately, but large in-rush currents occur causing perturbations to the power source and other loads

Engineering Contradiction:

Improvestartup speedVSAvoidin-rush current

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent segments the current path into two separate paths: a first path through a power converter circuit and a second path through electronic switches. This segmentation allows controlled current flow through each path separately, preventing the large in-rush currents that would occur with direct connection while still enabling rapid startup.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary action by using the power converter circuit to establish a controlled first current through the load before allowing the second current path to become active. This preliminary controlled charging prevents the sudden in-rush current surge that would occur with immediate full-power connection.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If protective measures are implemented to prevent in-rush current damage, then component safety is improved, but device complexity increases

Engineering Contradiction:

Improvecomponent safetyVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by designing the controller device to perform multiple functions: the power converter circuit and electronic switches work together to provide both current limiting protection and controlled charging in a single integrated architecture. This universal approach protects against in-rush currents while simplifying the overall design compared to multiple separate protective components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10361578B2Techniques for controlling current during power up in hot swap controllers

Publication Date: 2019.07.23 ANALOG DEVICES INC

AI summary

Using various circuits and methods, current can be controlled when a circuit board is plugged into a powered system using two charging paths so that a first current can be supplied between a supply voltage and the load in a first charging path during a first time period and a second current can be supplied between the supply voltage and the load in a second charging path during a second time period.