Power Supply Control Device for Semiconductor Switch Failure Detection
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Solution Overview
Problem
Existing power supply control devices for vehicles fail to detect half-on failures in semiconductor switches when both ends are connected to a power source, leading to potential overheating and switch failure due to current concentration.
Innovation Solution
A power supply control device with a temperature detection unit and switching control unit that switches semiconductor switches from OFF to ON if a threshold temperature is detected, and includes a relay contact to divert current away from failing switches, allowing current to flow through other switches and preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor switches are switched OFF to stop current flow when a short-circuit occurs on the anode side of parasitic diodes, then the source voltage on the anode side is maintained, but current concentrates in the FET with half-on failure causing excessive heat generation
Solution Approach 1:
A diode is introduced as an intermediary component connected between the anode side of the parasitic diodes and ground. This diode provides an alternative current path that prevents current concentration in the failed FET while maintaining source voltage stability, thereby resolving the contradiction between reliability and heat generation
Solution Approach 2:
The harmful current path through the failed FET is extracted by providing an alternative path through the newly added diode. This separates the current flow from the problematic component, allowing the system to maintain voltage stability without concentrating heat in the failed switch
2Ease of operation
If voltage between drain and source is used to detect half-on failures, then detection is simple, but half-on failures cannot be detected when both ends of the semiconductor switch have a power source connected
Solution Approach 1:
A detection diode is introduced as an intermediary measurement component connected to the anode side of the parasitic diodes. This diode enables voltage-based detection of half-on failures even when both ends of the semiconductor switch have power sources connected, maintaining detection simplicity while improving measurement accuracy
Solution Approach 2:
The detection approach is extended to a new dimension by measuring voltage at the anode side of the parasitic diodes rather than only at the drain-source terminals. This additional measurement point enables detection of half-on failures in circuits where both ends have power sources connected
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 detection and mitigation of half-on failures without relying on drain-source voltage measurements, preventing semiconductor switch burnout by distributing current and reducing temperature extremes.
Implementation Method 1
a temperature detection unit that detects a rise of temperature due to heat that is produced from at least one of the plurality of semiconductor switches
Data Source
AI summary
Provided is a power supply control device. The power supply control device includes a plurality of semiconductor switches that are connected in parallel between two power sources and control the supply of power to a load that is connected to the two power sources via the plurality of semiconductor switches, the power supply control device including a temperature detection unit that detects a rise of temperature due to heat that is produced from at least one of the plurality of semiconductor switches, and a switching control unit that executes control that switches the plurality of semiconductor switches from OFF to ON if the temperature detection unit detects a temperature that is at least a threshold temperature.