Power Source Switching Device With Diode Protection Against Battery Short-Circuit

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Solution Overview

Problem

Conventional electronic appliances with multiple batteries can experience short-circuiting when the control unit for power supply switching malfunctions, leading to adverse effects on the batteries and the appliance.

Innovation Solution

A power source switching device with a configuration of switch circuits and diodes that prevents short-circuiting between batteries by controlling the flow of current, using a logic circuit to ensure that at least one of the switch circuits remains off when both primary and secondary power sources are active.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a control unit performs switching control of power supply between multiple batteries, then power supply management is automated and efficient, but the system becomes vulnerable to short-circuiting when the control unit malfunctions

Engineering Contradiction:

Improveautomated power supply switchingVSAvoidsystem reliability under control unit malfunction

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

Diodes are introduced as intermediary components between the batteries and switch circuits. These diodes act as one-way valves for current flow, preventing reverse current that would cause short-circuiting between batteries when the control unit malfunctions. The diodes provide a passive safety mechanism that operates independently of the control unit's state.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements protective measures in advance by placing diodes in parallel with each switch circuit before any malfunction can occur. These diodes are pre-configured to block reverse current flow, cushioning the system against potential short-circuit damage that would otherwise occur during control unit failure modes.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If switch circuits are used for power supply switching, then power distribution is controlled and efficient, but short-circuiting occurs when both switch circuits are simultaneously on due to control unit failure

Engineering Contradiction:

Improvepower distribution efficiencyVSAvoidbattery short-circuiting

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful simultaneous conduction of both switch circuits into a beneficial protective mechanism. When both switches are on due to control unit failure, the diodes oriented in opposite directions block reverse current flow between batteries, transforming what would be a short-circuit condition into a safe state where both batteries can supply power to the load without damaging each other.

Inventive Principle:

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

3Adaptability or versatility

If multiple switch circuits are used for power source switching, then power supply flexibility is improved, but the circuit complexity and risk of short-circuiting increase

Engineering Contradiction:

Improvepower source switching flexibilityVSAvoidswitch circuit configuration complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Diodes are inserted as intermediary protective elements in parallel with each switch circuit. This addition maintains the flexibility of having multiple switchable power sources while introducing a simple passive component that prevents short-circuiting. The diodes add minimal complexity compared to the existing switch circuits while significantly improving system safety.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution ensures a stable power supply even when the control unit is in a malfunction state, preventing battery short-circuiting and maintaining normal operation of the electronic appliance.

Implementation Method 1

a first diode that is provided in parallel with the third switch circuit for allowing a current to flow from the first power source to the load section and while preventing a current from flowing from the second power source into the first power source

Methodology Applied

Scientific EffectDiode: Diode

Implementation Method 2

a second diode that is provided in parallel with the fourth switch circuit for allowing a current to flow from the second power source to the load section while preventing a current from flowing from the first power source into the second power source

Methodology Applied

Scientific EffectDiode: Diode

Data Source

PatentUS9152012B2Power source switching device and electronic appliance

Publication Date: 2015.10.06 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A power source switching device includes a first switch circuit provided between a first power source and a load section, a second switch circuit provided between a second power source and the load section, a third switch circuit provided between the first power source and the load section in series with the first switch circuit, a fourth switch circuit provided between the second power source and the load section in series with the second switch circuit, a logic circuit that controls the third and the fourth switch circuits to prevent at least one of the third and fourth switch circuits from turning on while both of the first and second switch circuits are in an on state, and a control circuit that controls the first switch circuit, the second switch circuit, and the logic circuit.