Three-Output DC Supply Short-Circuit Protection for Mid-Rail Output
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Solution Overview
Problem
Three output DC voltage supplies face issues with excessive power dissipation during short circuits, potentially damaging components due to power exceeding operating limits.
Innovation Solution
Incorporation of a short circuit protection module with transistors and current limiting elements to manage power dissipation by turning off transistors and reducing current flow during short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a short circuit occurs between the 0V and positive output voltage supply lines, then the power supply continues to operate, but the power dissipated through the transistor far exceeds the operating limits of the device
Solution Approach 1:
The patent applies preliminary anti-action by implementing a protection circuit that proactively limits current flow before excessive power dissipation can damage the transistor. The protection circuit includes a current limiting element and a control transistor that detects abnormal conditions and automatically restricts current, preventing the harmful effect of overheating before it occurs.
Solution Approach 2:
The patent uses an intermediary protection circuit between the power supply and the load to mediate and control current flow. This intermediary circuit includes transistors and current limiting elements that act as a buffer, allowing normal operation while blocking or limiting excessive current during short circuit conditions, thus protecting the main transistor from damage.
2Reliability
If the power dissipated through the transistor is limited to safe levels during a short circuit, then component damage is prevented, but the power supply cannot deliver full power under normal conditions
Solution Approach 1:
The patent implements dynamics by using transistors with variable resistance characteristics that automatically adjust their operating state based on load conditions. During normal operation, the transistors allow full power delivery, but during short circuit conditions, the transistor's resistance changes dynamically to limit current, thus adapting the power delivery capability to the operational requirements.
Solution Approach 2:
The patent applies feedback through a protection circuit that monitors the operating conditions and automatically adjusts current limiting based on detected anomalies. The control transistor responds to voltage changes caused by short circuit conditions, creating a feedback loop that reduces power dissipation when needed while maintaining full power capability during normal operation.
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
Limits power dissipation to safe levels, preventing component damage and reducing power loss during short circuits.
Implementation Method 1
a current limiting element connected to the emitter of the first transistor and configured to limit the power dissipated by the first transistor
Data Source
AI summary
A power supply circuit for providing a positive, intermediate, and negative voltage supply includes positive and negative DC voltage buses that connect to a power source; a first voltage divider that is connected between the positive and the negative DC voltage buses, that includes a first transistor connected to the negative DC voltage bus, and that provides the intermediate voltage supply; a second voltage divider that is connected between the positive and the negative DC voltage buses and that is connected to the first transistor; and a short circuit protection module that includes a second transistor connected between outputs of the first and second voltage dividers and connected to the first transistor and that includes a current limiting element connected to the first transistor and configured to limit power dissipated by the first transistor in the case of a short circuit to the intermediate voltage supply.