Semiconductor Overheating Protection Circuit Design
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Solution Overview
Problem
Conventional control circuits for semiconductor devices with overheating protection are complex, large, and expensive, leading to potential semiconductor element deterioration and incorrect shutdowns due to noise disturbances, which can result in lamp turn-off issues and increased fire risks when used in vehicular applications.
Innovation Solution
A control circuit that integrates a semiconductor element, temperature detecting circuit, and interrupting circuit on a single chip, featuring a drive circuit and current detecting circuit to manage drive voltage and prevent overheating, eliminating the need for a dedicated control unit and reducing size and cost while enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated control unit and extended interconnection are used to monitor the semiconductor device, then the overheating protection function is achieved, but the circuit becomes complex and large in size
Solution Approach 1:
The patent merges the temperature detecting circuit, latch circuit, gate interrupting circuit, and current detecting circuit into a single integrated chip with the semiconductor element. This eliminates the need for a separate dedicated control unit and extended interconnections, thereby reducing circuit complexity and size while maintaining the overheating protection function.
Solution Approach 2:
The semiconductor device performs self-monitoring and self-protection through integrated circuits on the same chip. The temperature detecting circuit continuously monitors the chip temperature, and the gate interrupting circuit automatically interrupts the gate input when overheating is detected, eliminating the need for external control units.
2Measurement precision
If repeated PWM control signal supply and protecting operations are performed to judge whether to stop supply, then the control accuracy is improved, but the semiconductor element deterioration due to overheating progresses
Solution Approach 1:
The latch circuit latches the detection output of the temperature detecting circuit in advance, and the gate interrupting circuit is prepared to interrupt the gate input immediately when the latched signal indicates overheating. This eliminates the need for repeated PWM control signal supply and protecting operations, thereby preventing semiconductor element deterioration while maintaining control accuracy.
Solution Approach 2:
The patent rushes through the protection process by immediately interrupting the gate input when overheating is detected, without performing repeated PWM control signal supply and protecting operations. This rapid response prevents further overheating and semiconductor element deterioration while maintaining control accuracy.
3Measurement precision
If the control means operates to stop PWM control signal supply due to disturbance noise, then the noise detection sensitivity is improved, but the lamp is incorrectly turned off
Solution Approach 1:
The current detecting circuit provides feedback on the actual current flowing through the semiconductor device. The control means combines this current feedback with temperature detection signals to distinguish between genuine overheating conditions and false signals caused by disturbance noise, thereby preventing incorrect lamp shutdown while maintaining noise detection sensitivity.
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
The solution simplifies the circuit design, reduces semiconductor element deterioration, and prevents incorrect shutdowns due to noise, ensuring high reliability and minimizing fire risks in vehicular applications by maintaining stable drive voltage and efficient overheating protection.
Implementation Method 1
a temperature detecting circuit for detecting temperature increase of the chip
Implementation Method 2
a current detecting circuit which outputs a detection signal when a drive current flowing through the semiconductor device exceeds a predetermined threshold current
Data Source
AI summary
A control circuit includes a drive circuit which applies a drive voltage to a semiconductor device having an overheating protection function according to an externally supplied signal; and a current detecting circuit which outputs a detection signal when a drive current flowing through the semiconductor device exceeds a predetermined threshold current. The semiconductor device incorporates a semiconductor element, a temperature detecting circuit for detecting temperature increase of a chip, and an interrupting circuit for interrupting an input to the semiconductor element according to a detection output of the temperature detecting circuit. The drive circuit turns off the semiconductor element and changes the drive voltage to a predetermined voltage so that the drive current exceeds the threshold current when the interrupting circuit interrupts an input to the semiconductor element, and keeps the drive voltage at the predetermined voltage while the detection signal is output from the current detecting circuit.