Hot Swap Controller Dynamic Current Limit Adjustment
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Solution Overview
Problem
Existing hot swap circuits use fixed current limits, leading to overdesign and inefficiency in power systems due to the inability to dynamically adjust current limits in response to changes in input or output voltage, resulting in excessive in-rush currents and potential system disturbances.
Innovation Solution
A hot swap circuit with a current limit circuit that automatically adjusts the current limit signal in response to changes in input or output voltage, using a sensing circuit to measure current and generate a current limit signal that controls the electronic switch, thereby reducing system overdesign and improving power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed current limit is used in hot swap circuits, then the circuit protection is simple and reliable, but the power system experiences overdesign and inefficiency due to inability to dynamically adjust to voltage changes
Solution Approach 1:
The patent implements dynamic current limit adjustment by detecting input voltage changes and automatically modifying the current limit signal accordingly. The circuit transitions from a static fixed current limit to a dynamic adaptive current limit that responds to real-time voltage conditions, eliminating overdesign while maintaining protection reliability.
Solution Approach 2:
The patent changes the current limit parameter based on input voltage conditions. When input voltage decreases, the current limit increases proportionally to maintain power delivery capability; when input voltage increases, the current limit decreases to prevent excessive in-rush currents. This parameter adaptation resolves the contradiction between reliable protection and efficient power utilization.
2Device complexity
If a fixed current limit is used in hot swap circuits, then the device complexity is low, but the power system suffers from overdesign and cannot adapt to changing voltage conditions
Solution Approach 1:
The patent employs feedback mechanisms where the input voltage detection circuit continuously monitors voltage conditions and feeds this information to the current limit adjustment circuit. This closed-loop feedback enables automatic adaptation to voltage changes without requiring complex external control systems, achieving high adaptability with minimal added complexity.
Solution Approach 2:
The current limit circuit performs self-adjustment based on detected voltage conditions without requiring external intervention or complex control algorithms. The circuit automatically modifies its own current limit signal in response to input voltage changes, providing adaptability through self-service operation while keeping the overall device complexity low.
3Power
If a higher fixed current limit is used to accommodate voltage drops, then the power delivery capability during voltage drops is improved, but excessive in-rush currents occur during normal operation
Solution Approach 1:
The patent dynamically changes the current limit parameter based on input voltage levels. During normal operation with adequate input voltage, the current limit is set to a lower value to prevent in-rush currents. When input voltage drops, the current limit automatically increases to maintain power delivery capability. This dynamic parameter adjustment eliminates the need for a consistently high current limit, preventing harmful in-rush currents while ensuring adequate power delivery during voltage drops.
Data Source
AI summary
In an example, a device for controlling an electronic switch between a power supply and a load includes a first device pin configured to be in communication with the electronic switch, a sensing circuit configured to be connected to an input voltage and to measure a current to the load, a control circuit configured to be in communication with the sensing circuit and the electronic switch, the control circuit configured to use a current limit signal to control operation of the electronic switch, and a current limit circuit configured to be in communication with the control circuit, the current limit circuit configured to generate the current limit signal representing a current limit and automatically adjust the current limit signal in response to a change in at least one of the input voltage and an output voltage.