Squib Control Circuit Dual Transistor Discharge

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Solution Overview

Problem

Existing control circuits for squibs face challenges in maintaining a charge for a predetermined period while ensuring prompt discharge within another predetermined period, balancing reliability and safety to prevent unintended energization.

Innovation Solution

The improved control circuit employs two transistors with different discharge rates to manage the capacitor charge, allowing sufficient energization for a first period and safe discharge within a second period, utilizing a first transistor for initial discharge and a second transistor for rapid discharge after the initial charge has been maintained for an extended duration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a capacitor is charged to enable squib energization, then the squib can be reliably activated when needed, but the capacitor must be promptly discharged within a predetermined period to prevent unintended activation

Engineering Contradiction:
Improvereliable squib activationVSAvoidunintended squib activation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The discharge function is segmented into two distinct stages using two different transistors: a first transistor provides a slower discharge rate for controlled energy dissipation, while a second transistor provides a faster discharge rate for rapid safety discharge. This segmentation allows the system to achieve both reliable activation and safe discharge prevention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The discharge rate is made dynamic by switching between two different discharge paths controlled by different transistors. The system transitions from a first discharge rate (when the first transistor conducts) to a second, faster discharge rate (when the second transistor conducts), allowing adaptive response to different operational states.

Inventive Principle:
Principle #15Dynamics

2Duration of action of moving object

If the capacitor charge is maintained for a predetermined period to allow FIRE command issuance, then operational flexibility is provided, but the charge must be dissipated within a subsequent predetermined period to ensure safety

Engineering Contradiction:
Improvecharge maintenance periodVSAvoiddischarge time
Core Design Contradiction:
Duration of action of moving objectVSLoss of time

Solution Approach 1:

The circuit is preliminarily configured with two discharge paths and control logic that anticipates the need for different discharge rates. The first transistor and its associated discharge path are prepared for initial charge maintenance, while the second transistor and faster discharge path are prepared for rapid safety discharge, ensuring both functions are ready in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The discharge rate parameter is changed by switching between two different transistor configurations. The system transitions from a first discharge rate parameter (slower) to a second discharge rate parameter (faster), allowing the same capacitor to serve both long-duration charge maintenance and rapid discharge functions.

Inventive Principle:
Principle #35Parameter changes

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 ensures the squib remains energizable for an extended period if needed but safely discharges within a predetermined time if the FIRE command is not issued, enhancing operational reliability and safety by preventing unintentional activation.

Implementation Method 1

a capacitor structured to at least temporarily store a charge

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

A first portion of the circuit includes a first transistor and is structured to discharge at a first rate a first portion of a charge stored by a capacitor

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

Another portion of the circuit includes a second transistor and is structured to discharge a second portion of the charge subsequent to the discharge of the first portion of the charge and at a second rate greater than the first rate

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2759059B1Improved squib control circuit
Publication Date: 2017.04.05 WESTINGHOUSE ELECTRIC CORP
  • EP2759059B1 patent drawingFigure 1~3

AI summary

An improved control circuit that is structured to energize another device such as a squib. A first portion of the circuit includes a first transistor and is structured to discharge at a first rate a first portion of a charge stored by a capacitor. Another portion of the circuit includes a second transistor and is structured to discharge a second portion of the charge subsequent to the discharge of the first portion of the charge and at a second rate greater than the first rate.