Multi-stage Overvoltage Protection Circuit with Adaptive Triggering
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Solution Overview
Problem
Existing multi-stage overvoltage protection circuits for information technology systems are not adaptable to a wide range of voltages and require a voltage-limiting component in the end device to manage overvoltages effectively.
Innovation Solution
A self-adjusting multi-stage overvoltage protection circuit that uses an evaluation device to generate a reference voltage, checks the current operating voltage against predetermined levels and rates of change, and activates a fine protection element via a control device to limit voltage and discharge interference current, eliminating the need for specialized protection devices at each voltage level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a gas discharge tube is used as a coarse protection element, then high current dissipation capability is achieved, but the protection level is too high to provide adequate protection for information technology devices
Solution Approach 1:
The protection circuit is divided into multiple stages: a first stage with a gas discharge tube for high current dissipation and a second stage with a fine protection element (TVS diode or Z diode) for precise voltage limiting. This segmentation allows each stage to perform its specialized function, resolving the contradiction between high power handling and adequate protection level.
2Reliability
If a fine protection element is added to provide adequate protection, then protection level adequacy is improved, but the circuit complexity increases
Solution Approach 1:
The coarse protection element and fine protection element are merged into a single multi-stage protection circuit with coordinated operation. The decoupling element bridges the two stages, allowing them to work together as an integrated system rather than separate circuits, thus providing adequate protection while managing complexity.
Solution Approach 2:
A decoupling element is introduced as an intermediary between the coarse and fine protection stages. This decoupling element coordinates the operation of both stages, enabling the fine protection element to activate only when necessary while allowing the coarse element to handle initial surge currents, thereby reducing overall circuit complexity.
3Adaptability or versatility
If separate protection devices are used for each voltage level, then voltage-specific protection is achieved, but the quantity of protection components increases
Solution Approach 1:
The multi-stage protection circuit is designed to operate across a wide voltage range by combining elements with different characteristics. The coarse protection element handles high-voltage surges while the fine protection element manages lower-voltage transients, allowing a single circuit to provide universal protection across multiple voltage levels without requiring separate devices for each level.
4Reliability
If the fine protection element is always active, then continuous protection is provided, but power consumption and interference with normal signals increase
Solution Approach 1:
The fine protection element is designed to dynamically activate only when overvoltage conditions are detected. The decoupling element and control circuitry enable the fine protection element to switch between high-impedance (off) and low-impedance (on) states, providing continuous protection capability while minimizing power consumption 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
The circuit automatically adapts to operating voltages, effectively limiting overvoltages and reducing the need for additional voltage-limiting components, providing comprehensive protection across a wide voltage range without requiring separate protection devices for each voltage level.
Implementation Method 1
A first stage is usually formed here by a component which can dissipate high currents but has a comparatively high response voltage. Such a component can be a gas discharge tube.
Implementation Method 2
there is usually a further stage in which there is a fine protection element, namely a Z diode, a TVS diode or similar
Implementation Method 3
There is at least one decoupling element between the coarse protection element and the fine protection element, which is used to coordinate the behavior of the aforementioned stages.
Data Source
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AI summary
The invention relates to a multi-staged overvoltage protection circuit, in particular for information-technology systems, comprising at least one coarse protection element and at least one fine protection element, wherein the at least one fine protection element can be activated by a triggering device depending on a threshold. According to the invention, the applied operating voltage is led to an evaluation device, which generates a reference voltage. Also provided is an evaluation unit, firstly for checking to see whether the current operating voltage is above the reference voltage, secondly for checking to see whether the voltage excess exceeds a previously determined level, and thirdly for establishing whether the rate of change of the operating voltage is greater than another previously determined value so that a transient overvoltage exists, wherein the triggering device then receives an activation signal from the evaluation device.