Interface Control Circuit with Capacitance-Based Electrolyte Detection

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Solution Overview

Problem

Existing interface control circuits, such as USB Type C compliant circuits, face issues with accelerated rusting when contacting electrolytic substances like water, leading to potential damage and reduced product lifespan due to electrolysis effects.

Innovation Solution

An interface control circuit with a protection circuit that detects contact pin capacitance to determine the presence of electrolytic substances and triggers protective measures, such as shutting down power or disabling signals, to prevent damage by using a capacitance sensing resistor or charging current source in series with the interface pin and a pull-up voltage, and a determination circuit to compare the capacitance to a threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the interface control circuit operates without protection when contacting electrolytic substances, then the circuit can function normally under various conditions, but the rusting process is expedited due to electrolysis effect causing damage and reduced lifespan

Engineering Contradiction:

Improveinterface circuit lifespanVSAvoidelectrolysis effect

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protection circuit performs preliminary detection of contact pin capacitance before allowing normal operation. When an attaching event is detected, the circuit immediately measures the capacitance value and compares it against a threshold to identify electrolytic substances, preventing electrolysis damage before it occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protection circuit acts as an intermediary between the interface transceiver circuit and the external environment. It monitors capacitance characteristics and controls the switching element to isolate or protect the circuit when electrolytic substances are detected, preventing direct harmful interaction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the interface control circuit adds a protection circuit to detect electrolytic substances, then the rusting process is slowed and lifespan is extended, but the device complexity increases

Engineering Contradiction:

Improveinterface circuit protectionVSAvoidcircuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protection circuit is merged with the existing interface control circuit architecture. The capacitance detection function is integrated into the same circuit board and shares common components such as the switching element and reference voltage sources, reducing overall system complexity while maintaining protection functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The protection circuit uses universal components that can serve multiple functions. The switching element can rapidly switch between normal operation and protection modes, and the capacitance detection mechanism can identify various electrolytic substances through their characteristic capacitance values, providing broad-spectrum protection with a single circuit design.

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

Effectively slows down the rusting process and extends the lifespan of the interface circuit by detecting and responding to electrolytic substances, ensuring continued functionality and safety.

Implementation Method 1

the protection circuit senses the contact pin capacitance of the first interface pin, and determines whether an electrolytic substance exists and is coupled to the first interface pin according to whether the contact pin capacitance is larger than a predetermined first capacitance threshold

Methodology Applied

Scientific EffectCapacitance sensing: Capacitance

Implementation Method 2

the rusting process of the contact pins may be expedited due to electrolysis effect

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Data Source

PatentUS10476257B2Interface control circuit and control method thereof

Publication Date: 2019.11.12 RICHTEK TECH

AI summary

An interface control circuit comprises an interface signal transceiver circuit coupled with an interface which includes at least one interface pin for transmitting and/or receiving an interface signal through the interface, and a protection circuit for generating a protection control signal according to a capacitance of a first interface pin. During a predetermined detection time period starting from an attaching event, the protection circuit senses the capacitance of the first interface pin, and determines that there is an electrolytic substance existing and coupled with the first interface pin when the capacitance is larger than a predetermined first capacitance threshold. The protection control signal triggers the interface signal transceiver circuit to execute a protection operation. The interface includes the first interface pin and the second interface pin, and the first interface pin and the second interface pin can be one same pin or separate different pins.