DC-DC Converter Diagnostic System Using Tri-State Buffer ICs
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Solution Overview
Problem
Conventional diagnostic systems for DC-DC voltage converters rely on a single integrated circuit, making it impossible to diagnose short circuits in FET switches if the diagnosis integrated circuit fails.
Innovation Solution
A diagnostic system utilizing a pair of tri-state buffer ICs to independently control and receive diagnostic signals from the DC-DC voltage converter, allowing for stable diagnosis even if one of the tri-state buffer ICs does not operate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single diagnosis integrated circuit is used to diagnose FET switches, then the device complexity is reduced, but the reliability of diagnosis is worsened because if the diagnosis integrated circuit does not operate, it is impossible to diagnose whether all FET switches are short-circuited
Solution Approach 1:
The patent divides the single diagnosis integrated circuit into multiple separate diagnosis integrated circuits (first diagnosis IC and second diagnosis IC). Each diagnosis IC independently monitors specific FET switches, so that if one diagnosis IC fails, the other can still provide diagnostic information. This segmentation resolves the contradiction by trading increased component count for improved diagnostic reliability.
Solution Approach 2:
The patent implements redundant diagnosis circuits that serve as backup for each other. The first and second diagnosis ICs are configured to monitor overlapping sets of FET switches, creating a cushioning effect where if one diagnosis IC fails, the other can compensate and still provide diagnostic coverage. This beforehand cushioning resolves the reliability concern while maintaining manageable system complexity.
2Reliability
If multiple diagnosis integrated circuits are used to improve diagnosis reliability, then the reliability of diagnosis is improved, but the device complexity increases
Solution Approach 1:
The first and second diagnosis ICs are designed with universal functionality to monitor multiple FET switches. Each diagnosis IC can independently diagnose short circuits in various FET switches within the DC-DC converter, allowing the system to achieve redundant coverage without requiring specialized circuits for each switch. This multi-functionality reduces the overall complexity compared to having dedicated diagnosis circuits for each FET.
Data Source
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AI summary
A diagnostic system for a DC-DC voltage converter having a high voltage switch, a low voltage switch, and a DC-DC voltage converter control circuit is provided. The system includes first and second tri-state buffer ICs and a microcontroller. The first tri-state buffer IC receives a first shutdown indicator voltage from the DC-DC voltage converter control circuit indicating that a first plurality of FET switches in a high side FET IC and a second plurality of FET switches in a low side FET IC have been transitioned to an open operational state. The first tri-state buffer IC outputs a second shutdown indicator voltage to the microcontroller that indicates that the first and second plurality of FET switches have been transitioned to the open operational state.