Voltage Regulator Current Limitation via Reference Voltage Adjustment
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Solution Overview
Problem
Current limitation circuits in voltage regulators face instability issues during power up and current limitation scenarios, leading to potential component overstress and complexity in stability analysis.
Innovation Solution
Implementing a current limitation system that adjusts the reference input voltage of the voltage regulator to manage output load current, placing the current limitation loop outside the regulator feedback loop to prevent overstress and simplify stability analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current limitation circuits sense output current and counter react on the main amplification stage, then current limitation function is achieved, but loop response is modified causing instability issues
Solution Approach 1:
The patent introduces an intermediary current limitation loop that operates outside the main regulator feedback loop. This separate loop senses output current and adjusts the reference voltage without directly interfering with the main amplification stage, thereby achieving current limitation while preserving the stability of the main regulator loop response.
2Reliability
If current limitation circuits act on the main amplification stage, then current limitation is achieved, but complexity in stability analysis increases
Solution Approach 1:
The patent segments the control system into two independent loops: the main regulator feedback loop and the current limitation loop. By separating these functions, the stability analysis of each loop can be performed independently, significantly reducing the overall complexity compared to analyzing a coupled system where current limitation directly affects the main amplification stage.
3Stability of the object's composition
If current limitation adjusts reference input voltage, then current limitation is achieved without modifying loop response, but additional control mechanism is required
Solution Approach 1:
The current limitation loop performs preliminary action by adjusting the reference voltage before the main regulator loop processes the control signal. This approach allows current limitation to be enforced without modifying the dynamic response characteristics of the main loop, as the reference voltage adjustment occurs in advance and does not create additional phase shifts or gain changes in the main feedback path.
Data Source
AI summary
This specification discloses methods and devices for limiting output current of a voltage regulator, in order to protect the voltage regulator against component overstress in case of output load current overloading. In some embodiments, a current limitation circuit acting on a reference input voltage of a voltage regulator can limit the maximum output load current of the voltage regulator. Once the current limitation circuit detects an over current load, the reference voltage is adjusted or decreased to limit the maximum output load current. Additionally, these methods and devices can be coupled easily with a slew rate control circuit to also limit the inrush current.