Overcurrent Protection Circuit Dynamic Gate Control
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Solution Overview
Problem
Existing overcurrent protection circuits for power supply devices face challenges in effectively balancing protection performance with load regulation, often resulting in increased complexity and cost due to the need for comprehensive control mechanisms.
Innovation Solution
An overcurrent protection circuit comprising an overcurrent limiting circuit, a current-voltage control circuit, and a control circuit that dynamically controls the output transistor's gate voltage to maintain output current within a limited value and ensure proportional output current to output voltage, with the control circuit stopping its intervention when the output voltage exceeds a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If comprehensive control mechanisms are implemented to ensure sufficient protection operating performance, then overcurrent protection reliability is improved, but device complexity increases
Solution Approach 1:
The control circuit is segmented into multiple functional blocks: overcurrent limiting circuit, current-voltage control circuit, and first control circuit. Each block performs a specific function, allowing the system to achieve comprehensive protection performance while maintaining manageable complexity through modular design.
Solution Approach 2:
The control circuit dynamically switches between different control modes based on output voltage conditions. When output voltage is below the threshold, current-voltage control is active; when it exceeds the threshold, only overcurrent limiting remains active. This dynamic adaptation optimizes protection performance while reducing unnecessary control complexity.
2Reliability
If comprehensive control mechanisms are implemented to ensure sufficient protection operating performance, then overcurrent protection reliability is improved, but manufacturing cost increases
Solution Approach 1:
The control circuit serves multiple functions: it provides overcurrent limiting protection, current-voltage control during normal operation, and automatic mode switching based on output voltage conditions. This multi-functionality eliminates the need for separate protection circuits, reducing component count and manufacturing cost while maintaining comprehensive protection performance.
Solution Approach 2:
The patent merges overcurrent protection functionality with the existing current-voltage control circuit. The first control circuit integrates both protection and control functions in a single block, reducing the need for separate dedicated protection hardware and thereby lowering manufacturing costs.
3Manufacturing precision
If the control circuit continuously controls the output transistor to maintain proportional output current to output voltage, then load regulation is improved, but the influence of protection operations on load regulation increases
Solution Approach 1:
The control circuit dynamically adjusts its control strategy based on output voltage levels. During normal operation (output voltage ≤ threshold), the current-voltage control circuit actively maintains proportional relationship between output current and voltage for optimal load regulation. During protection operation (output voltage > threshold), the first control circuit disengages the current-voltage control to minimize interference, allowing protection to take precedence while maintaining acceptable load regulation.
Data Source
AI summary
According to one embodiment, an overcurrent protection circuit for controlling an output transistor connected between a power source and an output terminal is provided. The overcurrent protection circuit has an overcurrent limiting circuit, a current-voltage control circuit, and a first control circuit. The current-voltage control circuit configured to control a gate voltage of the output transistor so that an output current is proportional to an output voltage of the output terminal Tout. The first control circuit is configured to allow the current-voltage control circuit to control the output transistor so that the output current is proportional to the output voltage when the output voltage is equal to or lower than a predetermined threshold voltage. The first control circuit is configured to allow the current-voltage control circuit to stop controlling the output transistor when the output voltage exceeds the threshold voltage.