Switch-Mode Converter Overcurrent Threshold Control for LPS Compliance
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Solution Overview
Problem
Existing overcurrent protection methods in switch-mode converters fail to meet limited power source (LPS) requirements, particularly when operating under low output voltages, leading to potential safety risks due to inconsistent overcurrent protection points.
Innovation Solution
An overcurrent protection circuit that adjusts the overcurrent reference threshold based on output voltage, using an overcurrent protection curve to ensure the switch-mode converter enters a protection state when necessary, thereby meeting LPS requirements and reducing safety risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed overcurrent protection threshold is used, then the protection circuit is simple to implement, but it fails to meet LPS requirements under varying output voltages leading to safety risks
Solution Approach 1:
The patent implements dynamic overcurrent protection by adjusting the protection threshold according to output voltage levels. The control circuit continuously monitors output voltage and dynamically modifies the overcurrent threshold to match LPS requirements at different operating conditions, transforming a static protection system into an adaptive one that maintains high reliability across varying loads
Solution Approach 2:
The patent changes the protection threshold parameter based on output voltage conditions. When output voltage varies, the control circuit adjusts the overcurrent threshold parameter accordingly, ensuring that the protection level adapts to different operating states and meets LPS requirements without requiring a completely complex protection architecture
2Reliability
If the overcurrent threshold is increased to ensure protection at low output voltages, then safety is improved, but false protection triggers occur at normal operating conditions
Solution Approach 1:
The patent applies different protection threshold levels for different operating conditions. Instead of using a single uniform threshold, the control circuit implements local quality by setting appropriate threshold values specific to each output voltage range, ensuring accurate protection activation without false triggers during normal operation
Solution Approach 2:
The protection threshold dynamically adapts to output voltage changes. When output voltage drops to low levels, the threshold adjusts to ensure adequate protection; when voltage returns to normal, the threshold correspondingly adjusts to prevent false protection triggers, maintaining continuous operational efficiency
Data Source
AI summary
A method of controlling a switch-mode converter can include: obtaining an overcurrent reference threshold according to an output voltage sampling signal indicative of an output voltage of the switch-mode converter; and generating an over current protection triggering signal in response to an output current sampling signal indicative of an output current of the switch-mode converter and the overcurrent reference threshold meet a predetermined criterion, thereby triggering the switch-mode converter to enter a protection state.