Semiconductor Switch Circuit for Wire Overheat Estimation
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Solution Overview
Problem
The increasing number of electronic devices in vehicles leads to a computational overload on MCUs, particularly in managing overheating protection, as discrete load current detection results in errors and increased costs due to resource demands for A/D conversion and square calculation processes.
Innovation Solution
A semiconductor switching device with integrated load current detection, square calculation, and temperature estimation circuits reduces MCU load by performing square integration and temperature estimation directly, using analog-to-digital conversion and thermal modeling to accurately monitor wire temperatures and cut off current supply when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If discrete load current detection is performed by MCU, then control flexibility is maintained, but measurement precision deteriorates due to insufficient detection of short current increases or surge fluctuations
Solution Approach 1:
The patent replaces the MCU's discrete digital sampling method with a continuous analog detection circuit that directly monitors load current. The analog current detection circuit continuously tracks current variations without the quantization and sampling limitations of digital systems, thereby detecting even brief current surges or fluctuations that discrete sampling would miss, while the MCU retains its control flexibility through digital processing of the analog signal.
2Device complexity
If square calculation and temperature estimation are performed by MCU, then system integration is reduced, but device complexity increases due to computational load and A/D conversion resources
Solution Approach 1:
The patent extracts the computationally intensive square calculation and temperature estimation functions from the MCU and implements them in dedicated hardware circuits. The square calculation circuit directly computes the square of the detected current value, and the temperature estimation circuit uses this squared value along with environmental temperature to estimate wire temperature. This extraction eliminates the need for MCU to perform complex calculations and A/D conversion, significantly reducing computational load while maintaining system integration.
3Measurement precision
If multiple circuits are used for overheating determination, then temperature monitoring accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple functions into an integrated temperature estimation circuit that simultaneously performs square calculation, environmental temperature compensation, and wire temperature estimation. Instead of using separate circuits for each function, the design combines these operations in a single integrated circuit block that processes the squared current value and environmental temperature input to produce the wire temperature estimate, thereby achieving accurate temperature monitoring while reducing component count and manufacturing cost.
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 approach allows for inexpensive and highly accurate load current square integration and wire temperature estimation, reducing computational burden on MCUs and minimizing errors, thereby enhancing safety and reducing costs.
Implementation Method 1
a load current detector that detects the load current flowing through the switch
Implementation Method 2
a square calculator that outputs a square value of the load current detected by the load current detector
Implementation Method 3
the voltage exceeds the triangle wave signal, the overheating protection device outputs the sense current to the thermal equivalent circuit, and accumulates a charge in the capacitor of the thermal equivalent circuit corresponding to the current value and the time the current has flowed
Implementation Method 4
accumulates a charge in the capacitor of the thermal equivalent circuit corresponding to the current value and the time the current has flowed
Implementation Method 5
an arithmetic circuit that receives a digitally converted environmental temperature signal and the squared value, and estimates temperature of the electric wire based on the digitally converted environmental temperature signal and the squared value
Data Source
AI summary
A semiconductor switching device according to one or more embodiments may include a switch that is connected between a power supply connected from outside of the semiconductor switching device and a load through an electric wire, and turns on and off power supply to the load, a load current detector that detects the load current flowing through the switch, and a square calculator that outputs a square value of the load current detected by the load current detector. In one or more embodiments, the switch may turn on and off the power supply to the load based on a control command.