Interface Protection Circuit for NTC Sensor Overvoltage
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Solution Overview
Problem
In lithium-ion battery packs, improper connection of temperature sensors can lead to overheating, thermal imbalances, and accelerated aging due to positive feedback from NTC temperature sensors when voltage is applied directly to them.
Innovation Solution
A protective device for electronic components connected to an interface, featuring a detection apparatus for voltage and current, a monitoring apparatus, and an electronic switch that disconnects the component from the interface when an impermissibly high voltage is detected, allowing for high-impedance disconnection and reconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage is applied directly to the NTC temperature sensor, then the sensor can detect temperature, but the sensor heats up due to power conversion causing lower resistance and increased power (positive feedback)
Solution Approach 1:
A protective device is introduced as an intermediary between the voltage source and the NTC temperature sensor. This protective device includes a detection apparatus for detecting voltage and/or current, and an electronic switch that disconnects the sensor when impermissibly high voltage is detected, preventing direct voltage application that causes overheating while allowing normal operation when voltage is within safe limits.
2Reliability
If an electronic switch is used to disconnect the sensor in case of fault, then current limitation is achieved, but the device complexity increases
Solution Approach 1:
The protective device incorporates a detection apparatus that automatically detects impermissibly high voltage or current conditions and triggers an electronic switch to disconnect the NTC sensor without requiring external intervention. The system serves itself by monitoring its own operating conditions and taking protective action when thresholds are exceeded, reducing the need for additional complex control systems.
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
Prevents damage to electronic components by disconnecting them from the interface before any damaging rise in temperature occurs, effectively preventing thermal imbalances and extending the lifespan of lithium-ion battery packs.
Implementation Method 1
A sensor that changes its ohmic resistance depending on the temperature is often used as temperature sensor. If this resistance becomes lower at a higher temperature, this is referred to as an NTC (negative temperature coefficient).
Implementation Method 2
a detection apparatus for detecting electrical voltage and/or electric current at the electronic component
Implementation Method 3
an electronic switch, connected in series with the electronic component, for disconnecting the electronic component from the electrical interface in the event that an impermissibly high electrical voltage is applied to the electronic component
Data Source
AI summary
The disclosure relates to a protective device for an electronic component connected to an electrical interface, comprising: a detection device for detecting electrical voltage and/or electrical current at the electronic component; a monitoring device; an electronic switch connected in series with the electronic component for disconnecting the electronic component from the electrical interface in the event that an impermissibly high electrical voltage is applied at the electronic component, wherein at least double the nominal voltage is identified as an impermissibly high electrical voltage, wherein in the event that an impermissibly high electrical voltage is no longer detected at the electronic component, the electronic component can be connected to the interface by means of the electronic switch.