Switching Mode Power Supply Over Current Protection Anti-Surge Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing over current protection schemes in switching mode power supplies often fail to distinguish between surge events and over current events, leading to false triggering and inefficient protection, particularly in applications like servers and computing, where sudden voltage drops are common.
Innovation Solution
A driving circuit and method that includes an over current comparison circuit, a watch-dog circuit, and an on moment control circuit to manage the switching of the power supply, allowing for precise timing to differentiate between surge and over current events, thereby preventing false shutdowns and ensuring effective protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the over current protection circuit triggers shutdown upon detecting current exceeding the threshold during surge test, then the power supply is protected from potential damage, but the output voltage drops dramatically and the power supply must be restarted, causing service interruption
Solution Approach 1:
The patent applies dynamics by making the over current threshold adaptive rather than fixed. The threshold dynamically changes based on the operating state: during surge tests it allows higher current levels, while during normal operation it maintains stricter limits. This resolves the contradiction by enabling the system to maintain both protection reliability and continuous operation through state-dependent threshold adjustment.
Solution Approach 2:
The patent changes the parameter of the current threshold based on different operating conditions. By detecting whether the system is in surge test mode or normal operation mode, the circuit adjusts the threshold parameter accordingly, allowing surge currents during testing without false triggering while maintaining protection during normal operation.
2Device complexity
If the over current protection uses a fixed threshold value, then the protection logic is simple, but it cannot distinguish between surge events and actual over current events, leading to false triggering
Solution Approach 1:
The patent transforms the static threshold into a dynamic one that adapts to different operating modes. The threshold is no longer fixed but changes based on whether the system detects surge test conditions or normal operation, thereby improving measurement precision for event differentiation without significantly increasing device complexity.
Solution Approach 2:
The patent changes the threshold parameter based on the detected operating state. By introducing mode detection capability, the system adjusts the current threshold parameter to appropriate levels for each mode, enabling accurate distinction between surge events and over current events while maintaining relatively simple protection logic.
3Reliability
If the over current protection shuts down the entire power supply, then comprehensive protection is provided, but the power supply cannot resume operation without restart, causing service interruption
Solution Approach 1:
The patent applies dynamics by implementing adaptive threshold adjustment based on operating mode detection. This allows the system to differentiate between temporary surge events and persistent over current conditions, providing comprehensive protection while avoiding unnecessary shutdowns that would cause service interruption and restart delays.
Solution Approach 2:
The patent changes the current threshold parameter dynamically based on whether the system is in surge test mode or normal operation. This parameter adaptation enables the protection circuit to maintain comprehensive coverage for actual over current events while tolerating surge events, thereby preventing unnecessary shutdowns and avoiding loss of time associated with restarts.
Data Source
AI summary
A switching mode power supply preventing false triggering of an over current protection due to a surge pulse. The switching mode power supply has a switch and an inductor. An inductor current flows through the inductor. The switching mode power supply turns off the switch and meanwhile starts timing for a preset period of time when the inductor current is larger than a preset value. The switch is kept off during the preset period of time and is then turned on when the preset period of time expires.