Switched Mode Power Supply Controller Cycle Completion
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Solution Overview
Problem
In switched mode power supplies, fault conditions such as power failures or faults lead to immediate termination of switching, resulting in shortened turn-on times and voltage oscillations across output capacitors, which can cause voltage spikes and require additional design considerations to withstand these spikes.
Innovation Solution
A switched mode power supply controller with a full switching cycle detection circuit that disables switching only after completion of a current switching cycle, and a method involving gate pulse generators and control logic to ensure that switching is terminated only after a full cycle is completed, preventing voltage spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If switching is terminated immediately upon fault detection, then fault response time is reduced, but voltage spikes occur due to shortened turn-on times
Solution Approach 1:
The controller detects fault conditions in advance and prepares to terminate switching, but delays the actual termination until the current switching cycle is complete. This preliminary detection combined with delayed action allows the system to maintain normal switching operation through the current cycle, preventing voltage spikes while being ready to respond to faults.
Solution Approach 2:
The system allows the current switching cycle to complete naturally as a cushioning period, preventing the abrupt termination that would cause voltage spikes. This cushioning approach ensures that switching is only terminated at appropriate boundaries, protecting the system from harmful voltage transients while maintaining fast fault response capability.
2Object-affected harmful factors
If switching is delayed until full cycle completion, then voltage spikes are reduced, but fault response time increases
Solution Approach 1:
The controller performs preliminary fault detection and validation, confirming the fault condition persists for a predetermined period before initiating switching termination. This preliminary action distinguishes between transient and permanent faults, ensuring switching is only delayed for genuine faults while maintaining rapid response to actual fault conditions.
Solution Approach 2:
The system dynamically adjusts its response based on the duration and persistence of the fault condition. For transient faults, switching continues uninterrupted; for persistent faults, switching is terminated after the current cycle completes. This dynamic approach optimizes both voltage spike prevention and fault response time based on actual fault characteristics.
3Reliability
If immediate switching termination is implemented, then system safety is improved, but switch design complexity increases to withstand voltage spikes
Solution Approach 1:
The controller implements a cushioning mechanism that prevents abrupt switching termination by waiting for the current switching cycle to complete. This cushioning approach eliminates voltage spikes that would otherwise require switches to be designed with enhanced voltage withstand capability, thereby reducing switch design complexity while maintaining system safety.
Solution Approach 2:
The system converts the potentially harmful effect of delayed fault response into a benefit by using the natural switching cycle boundary as a termination point. This approach transforms what could be seen as a delay into a protective mechanism that prevents voltage spikes, allowing simpler switch designs while maintaining safety.
Data Source
AI summary
In some embodiments, upon detecting a fault condition, switching in a switched mode power supply is disabled only after a current switching cycle of the switched mode power supply is completed.