FET Malfunction Detection Circuit for Power Supply Reliability
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Solution Overview
Problem
Conventional power supply devices cannot perform real-time malfunction checks on FETs while in use due to cumbersome procedures, and malfunctions are often caused by thermal destruction leading to short-circuits, which are difficult to detect immediately.
Innovation Solution
An FET for malfunction check is connected between the gate and source of the FET for power-source output control, with a malfunction determination circuit monitoring the output voltage to detect short-circuits in real time, allowing for immediate detection of malfunctions without disconnecting the load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a monitoring circuit is provided to detect FET malfunction, then the reliability of power supply device is improved, but the device complexity increases and real-time detection capability deteriorates
Solution Approach 1:
A malfunction check FET is introduced as an intermediary component connected between the gate and source of the power-source output control FET. This intermediary FET enables real-time malfunction detection by monitoring voltage changes without requiring complex external monitoring circuits, thus improving reliability while avoiding excessive device complexity
Solution Approach 2:
The malfunction check FET enables the system to self-diagnose FET malfunctions by monitoring its own operational state through voltage changes. The system uses its existing components (the malfunction check FET and voltage monitoring capability) to detect malfunctions, eliminating the need for separate complex monitoring circuits
2Ease of operation
If malfunction check is carried out by disconnecting the load, then the monitoring procedure is simplified, but the productivity decreases and real-time detection is lost
Solution Approach 1:
The malfunction check FET enables continuous real-time monitoring of FET operational state during normal power supply operations. The monitoring occurs continuously without interrupting the power supply to the load, maintaining both operational continuity and detection capability simultaneously
Solution Approach 2:
The malfunction check FET is pre-positioned between the gate and source of the power-source output control FET, ready to detect malfunctions as they occur. This preliminary setup eliminates the need for separate load disconnection steps, enabling immediate real-time detection while maintaining load connectivity
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
Enables real-time malfunction detection and immediate alerts for FET short-circuits, enhancing the reliability and operational safety of the power supply device by allowing continuous monitoring without the need for a special check mode.
Implementation Method 1
a malfunction determination circuit determines whether the FET for power-source output control is operating normally or not, by monitoring output voltage of the FET for malfunction check
Data Source
AI summary
An FET for malfunction check is connected between the gate and source of an FET for power-source output control, which is connected in series in a power output line from a battery used as a power source for a load. A malfunction determination circuit determines whether the FET for power-source output control is operating normally or not, by monitoring output voltage of the FET for malfunction check. Further, the malfunction determination circuit identifies malfunction of the FET for power-source output control due to short-circuiting during actual use.