Dynamic Current Limiting Threshold Control for Switch Transistors
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Solution Overview
Problem
Current limiting techniques face challenges in timely switching off transistors during sudden loading or short circuits due to time delays, leading to excessive heat loss and turn-off stress, especially when the current limiting threshold is fixed and cannot be easily adjusted to compensate for changing delays.
Innovation Solution
A regulation method and device that dynamically adjusts the current limiting threshold based on current limiting actions and inductive current levels, decreasing the threshold when no limiting occurs or the current is low and increasing it when limiting occurs or the current is high, ensuring proper load-carrying capacity and preventing excessive current uprushes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed current limiting threshold is used, then the device structure is simple, but the current cannot be timely limited when time delay varies, causing excessive heat loss and turn-off stress
Solution Approach 1:
The patent applies dynamics by transforming the fixed current limiting threshold into a dynamic, adjustable threshold. The control device dynamically adjusts the current limiting threshold based on real-time detection of current limiting actions and inductive current levels, allowing the threshold to adapt to varying time delays and operating conditions, thereby maintaining effective current limiting without excessive complexity.
Solution Approach 2:
The patent implements feedback by detecting current limiting actions and inductive current levels in real-time, then using this feedback information to adjust the current limiting threshold. This closed-loop control ensures the threshold remains appropriate under varying conditions, resolving the contradiction between structural simplicity and limiting effectiveness.
2Speed
If the current limiting threshold is decreased to compensate for time delay, then the current can be limited more timely, but the load-carrying capacity is reduced and heat loss increases
Solution Approach 1:
The patent uses dynamics to adjust the current limiting threshold in real-time based on operating conditions. When time delay is detected, the threshold is temporarily lowered to ensure timely current limiting; when normal operation is detected, the threshold is raised to maintain load-carrying capacity and reduce heat loss. This dynamic adjustment resolves the contradiction between response speed and energy loss.
Solution Approach 2:
The patent changes the current limiting threshold parameter dynamically based on detected conditions. By adjusting this key parameter according to real-time feedback on current limiting actions and inductive current, the system achieves timely current limiting only when necessary, while maintaining optimal load-carrying capacity during normal operation, thus reducing overall heat loss.
3Power
If the current limiting threshold is increased to maintain load-carrying capacity, then the load-carrying ability is improved, but the current cannot be limited timely during sudden loading or short circuit
Solution Approach 1:
The patent applies dynamics by making the current limiting threshold adjustable rather than fixed. During sudden loading or short circuit, the system detects current limiting actions and temporarily lowers the threshold to ensure timely protection. During normal operation, the threshold is maintained at a higher level to preserve load-carrying capacity, thus resolving the contradiction between power capability and protection reliability.
Solution Approach 2:
The patent implements preliminary action by detecting current limiting actions in advance and proactively adjusting the current limiting threshold before excessive current can cause damage. This early detection and adjustment mechanism ensures timely protection during abnormal conditions while maintaining high load-carrying capacity during normal operation.
Data Source
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AI summary
A regulation method for current limiting control, comprising: S1. regulating a current limiting threshold in real time based on a current limiting action; S2. controlling switch transistors based on the regulated current limiting threshold. By implementing the regulation method and device, it is made possible to regulate a current limiting threshold in real time directly based on a current limiting action, such that a current uprush in a first PWM wave will be significantly suppressed at the time of sudden loading or occurrence of a short circuit. Further, by regulating the current limiting threshold in real time based on the current limiting action and an inductive current, it is not only made possible to satisfy proper load-carrying capability, but also made possible to prevent a current uprush in a first PWM wave from being too high at the time of sudden loading or occurrence of a short circuit.