Switch Transistor Protection Using Junction Temperature Control
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Solution Overview
Problem
Conventional circuit protection devices struggle to ensure that switch transistors operate within a safe operating area, particularly due to difficulties in accurately determining and managing power, over-current, and over-temperature limits, leading to potential damage from overheating.
Innovation Solution
A switch transistor protection device utilizing a voltage/current detection mechanism and determination device to monitor and control the junction temperature, implementing power, over-temperature, and over-current protections based on a fixed 'single temperature' parameter, preventing the transistor from exceeding its maximum junction temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional circuit protection devices use complex safe operating area data for design, then power limitation and protection capability are improved, but device complexity and design difficulty increase
Solution Approach 1:
The patent transforms the complex multi-parameter safe operating area problem into a single temperature parameter control problem. By converting power consumption and current limits into equivalent temperature values, the system simplifies the protection mechanism while maintaining comprehensive protection capability. The determination device compares temperature parameters to decide whether to activate protection, avoiding complex multi-parameter analysis.
Solution Approach 2:
The single temperature parameter serves multiple protection functions simultaneously. The same temperature parameter is used for power limitation, over-current protection, and over-temperature protection, making the protection device universal and eliminating the need for separate complex control mechanisms for each protection type.
2Reliability
If conventional protection devices use multiple separate protection mechanisms, then comprehensive protection is improved, but device complexity and parameter acquisition difficulty increase
Solution Approach 1:
The patent merges power limitation, over-current protection, and over-temperature protection into a single unified temperature-based control mechanism. Instead of implementing three separate protection circuits, the system converts all protection criteria into temperature parameters and uses one determination device to handle all protection decisions, significantly reducing overall system complexity.
Solution Approach 2:
The temperature parameter acts as a universal indicator that simultaneously represents power consumption levels, current magnitude, and thermal state. This single parameter enables the determination device to perform multiple protection functions through a unified decision-making process.
3Reliability
If conventional devices ensure operation within maximum margin of safe operating area, then reliability is improved, but it is difficult to ensure maximum margin utilization
Solution Approach 1:
The system continuously monitors the temperature parameter and provides feedback to the determination device, which adjusts the control signal to the switch transistor accordingly. This closed-loop feedback mechanism ensures that the transistor operates precisely at the maximum safe margin by dynamically adjusting operation based on real-time temperature conditions, preventing both under-utilization and over-stress.
Data Source
AI summary
A switch transistor protection device includes a voltage/current detection device and a determination device. The voltage/current detection device is electrically connected to a switch transistor, and used to detect a voltage of the gate, the body, the source or the drain of the switch transistor, or used to detect a current of the source or the drain of the switch transistor to generate a reference voltage. The determination device is electrically connected to the voltage/current detection device and the switch transistor, and used to determine whether the reference voltage exceeds an overcurrent voltage or a fixed maximum junction temperature voltage corresponding to a maximum junction temperature of the switch transistor. When the determination device determines the reference voltage exceeds the maximum junction temperature voltage or the overcurrent voltage, the determination device generates a control signal to the gate, the body, the source or the drain of the switch transistor.