USB Type-C Port Short Protection Using Thermistor and MOSFET
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Solution Overview
Problem
The increased power delivery capabilities of USB Type-C connectors pose safety risks due to potential short circuits, which can lead to overheating and damage to the port or connected components, as well as user safety hazards.
Innovation Solution
A short circuit protection circuit utilizing a negative temperature coefficient thermistor and MOSFET to detect excessive heat from short circuited power supply lines, turning off power delivery when the thermistor heats up, mimicking a disconnected state and preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If USB Type-C port delivers increased power (up to 100 watts), then power delivery capability is improved, but safety risk increases due to potential short circuits causing overheating
Solution Approach 1:
The protection circuit is pre-configured with thermistors positioned near power delivery components and circuitry that monitors temperature conditions before dangerous overheating occurs. When abnormal temperature rise is detected indicating a potential short circuit, the circuit automatically interrupts power delivery through controlled switching elements, preventing the harmful effect before it can cause damage
Solution Approach 2:
Temperature-sensitive components (thermistors) serve as intermediary sensors that detect thermal conditions and translate them into electrical signals. These intermediaries bridge the gap between physical temperature conditions and the control circuitry, enabling automatic protection without direct user intervention or complex monitoring systems
2Reliability
If temperature monitoring and automatic shutdown circuitry is added, then safety is improved, but device complexity increases
Solution Approach 1:
The protection functionality is merged with existing power delivery circuitry by integrating temperature-sensitive components directly into the power path. The same circuit elements that manage power delivery also handle protection functions, eliminating the need for separate monitoring systems and reducing overall device complexity while maintaining high safety standards
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 reduces the risk of port damage and user safety hazards by ensuring power delivery is halted when a short circuit occurs, maintaining safe temperatures and preventing burns or shocks.
Implementation Method 1
A short circuit protection circuit utilizing a negative temperature coefficient thermistor and MOSFET to detect excessive heat from short circuited power supply lines
Implementation Method 2
A short circuit protection circuit utilizing a negative temperature coefficient thermistor and MOSFET to detect excessive heat from short circuited power supply lines, turning off power delivery when the thermistor heats up
Data Source
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AI summary
A short circuit protection circuit may comprise a first configuration channel line extending from a first connector, a first resistor connected to the first configuration channel line; a voltage divider connected to a junction point on the first configuration channel line, the voltage divider comprising a second resistor and a thermistor, and a field effect transistor (FET) comprising a source, gate, and drain. The thermistor may be connected to a ground line. The drain of the FET may be connected to the first resistor, the source of the FET may be connected to the ground line, and the gate of the FET may be connected to a second junction point between the second resistor and thermistor of the voltage divider.