Semiconductor Overheat Detection via Thermal RC Network
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Solution Overview
Problem
Existing semiconductor devices for power management, such as those used in automobiles, face challenges in accurately detecting overheating due to insufficient precision in temperature detection methods, particularly in first-order and second-order approximations, and reliance on diodes for overtemperature detection.
Innovation Solution
A semiconductor device incorporating a current generation circuit, a temperature sensor, and a resistor-capacitor network that models thermal resistance and capacitance between the transistor and the temperature sensor, enhancing overheating detection accuracy by incorporating a differential amplifier and comparator circuits to generate a current proportional to power consumption and monitor temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If first-order or second-order approximate calculation is used to determine temperature based on distance from temperature sensing diode, then temperature detection can be implemented, but detection accuracy is insufficient
Solution Approach 1:
The patent introduces a thermal resistance element as an intermediary component between the power MOSFET and the temperature sensing diode. This thermal resistance element actively models the thermal path, allowing the temperature sensing diode to accurately reflect the junction temperature of the power MOSFET through controlled thermal coupling, thereby resolving the accuracy issue of distance-based approximation methods.
2Measurement precision
If diodes are used for overtemperature detection, then overtemperature detection can be achieved, but detection accuracy is not high
Solution Approach 1:
The temperature sensing diode serves as an intermediary that indirectly measures the junction temperature of the power MOSFET through thermal coupling via the thermal resistance element. This approach maintains detection accuracy while avoiding the need for complex direct measurement circuits, as the diode's voltage characteristics provide sufficient temperature information when properly coupled.
Solution Approach 2:
The patent replaces complex electronic temperature measurement circuits with a thermal-physical model using the thermal resistance element and temperature sensing diode. This substitution leverages physical thermal coupling laws instead of complex electrical measurement systems, achieving accurate detection with simpler circuitry.
3Measurement precision
If thermal resistance element is disposed between power MOSFET and temperature sensing diode, then temperature detection accuracy is improved, but chip area increases
Solution Approach 1:
The patent segments the thermal path into distinct functional zones: the power MOSFET generates heat, the thermal resistance element models and controls thermal flow, and the temperature sensing diode measures temperature. This segmentation allows each component to be optimized for its specific function while maintaining compact integration, reducing overall chip area compared to alternative designs.
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 configuration enables high-accuracy overheating detection, preventing thermal destruction while minimizing performance degradation and chip area increase, allowing for precise monitoring and control of semiconductor devices.
Implementation Method 1
a thermal resistance element disposed between the power MOSFET and the temperature sensing diode
Implementation Method 2
the temperature sensing diode is coupled to the power MOSFET through a thermal resistance element
Data Source
AI summary
A semiconductor device includes a first transistor that flows a current to a load, a current generation circuit that outputs a current corresponding to a power consumption of the first transistor, a temperature sensor, a resistor-capacitor network coupled between the current generation circuit and the temperature sensor and an overheat detection circuit coupled to a connection point of the current generation circuit and the resistor-capacitor network, wherein the resistor-capacitor network comprises a resistor and a capacitor corresponding to a thermal resistance and a thermal capacitance between the first transistor and the temperature sensor.