Electronic Fuse Clamp Circuit for Fast Short-Circuit Shutdown
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Solution Overview
Problem
Existing electronic fuses struggle to balance accuracy and speed in responding to over-current conditions, particularly short-circuits, leading to increased complexity, size, and power consumption.
Innovation Solution
Incorporating a clamp circuit that supplements the current control loop to quickly respond to short-circuit conditions, using a diode-connected transistor to sense current and generate a clamp signal, allowing for faster response times and reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a traditional current control loop is used to detect over-current conditions, then the electronic fuse can provide protection, but the response time is slow and the system complexity increases
Solution Approach 1:
The patent extracts the short-circuit detection function from the main current control loop by implementing a separate clamp circuit with a diode-connected transistor. This dedicated detection path operates independently and directly triggers the power transistor shutdown, eliminating the need for complex control loop processing and achieving faster response time.
Solution Approach 2:
The diode-connected transistor serves as an intermediary element that directly senses the voltage drop across the power transistor during short-circuit conditions. This intermediary provides a simple voltage signal that immediately indicates over-current status, bypassing complex control logic and enabling rapid protection response.
2Reliability
If the electronic fuse responds faster to short-circuits, then protection is improved, but power consumption increases
Solution Approach 1:
The clamp circuit is designed to be active only locally during short-circuit conditions when the diode-connected transistor conducts. During normal operation, the detection circuit consumes minimal power, but immediately activates with high reliability when voltage drop exceeds the diode threshold, providing localized high-performance detection exactly when needed.
Solution Approach 2:
The detection circuit uses simple, low-cost transistor and diode components that are activated temporarily only during fault conditions. The diode-connected transistor acts as a disposable sensing element that provides reliable short-circuit detection for the duration of the fault event without requiring continuous high-power 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
The clamp circuit enables the electronic fuse to accurately and swiftly react to short-circuits, minimizing over-current periods and reducing power consumption and complexity compared to traditional approaches.
Implementation Method 1
a diode-connected transistor coupled between the input of the electronic fuse and in series with the sense transistor, the diode-connected transistor configured to conduct while the short-circuit condition exists so that the sense transistor conducts a sensed current corresponding to a current conducted by the power transistor
Data Source
AI summary
An electronic fuse that includes a clamp circuit to enhance the protection provided by the electronic fuse. The clamp circuit can detect a short circuit condition quickly and transmit a trigger signal to a controller so that a power transistor of the electronic fuse can be turned-OFF before the current through the power transistor causes overheating or damage. The clamp circuit is a dedicated circuit for short-circuit detection that can work with other current control circuits of the electronic fuse. The clamp circuit does not increase the power consumed by the electronic fuse while not in the short circuit condition. The clamp circuit is small and fast because it can use low-voltage devices, even as high voltages are present at the input and output of the electronic fuse.