Flyback SMPS Saturation Control via Primary Stroke Comparison
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Solution Overview
Problem
Switched-mode power supplies (SMPS) are susceptible to transformer saturation, which degrades their power conversion efficiency, and existing solutions require additional pins or complex control mechanisms, making them costly and inefficient.
Innovation Solution
A saturation controller for flyback SMPS that measures the length of primary strokes, compares them to previous strokes, and adjusts the switching period time to prevent transformer saturation, using existing pins and simpler control signals without requiring an additional pin for zero-voltage crossing detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional saturation control methods are used, then transformer saturation is reduced, but additional IC pins and complex control mechanisms are required
Solution Approach 1:
The system uses its own existing pins (PIN1 and PIN2) to perform saturation control functions. The controller utilizes the primary winding signal and secondary winding feedback that already exist in the flyback converter circuit, eliminating the need for external saturation detection components.
Solution Approach 2:
Existing pins in the controller are made to serve multiple functions. PIN1 is used for both primary signal detection and saturation control, while PIN2 handles both secondary feedback and saturation prevention, making the control mechanism more compact and cost-effective.
2Reliability
If zero-voltage crossing detection is implemented, then saturation control is improved, but additional IC pins are required
Solution Approach 1:
The controller performs zero-voltage crossing detection using existing internal circuitry and signals already present at PIN1 and PIN2. The system detects when the transformer voltage crosses zero by monitoring the existing winding signals, avoiding the need for dedicated detection pins.
Solution Approach 2:
The saturation control function is merged with the existing feedback and primary signal processing functions. The same pins that handle normal converter operation are also used for saturation detection and control, consolidating multiple functions into existing hardware resources.
Data Source
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AI summary
Embodiments of a saturation controller for a flyback switched-mode power supply (SMPS) and a method for saturation control for a flyback SMPS involve measuring a length related to a primary stroke in the flyback SMPS, comparing the length related to the primary stroke to a length related to a previous primary stroke in the flyback SMPS to generate a comparison result and adjusting a switching period time of the flyback SMPS based on the comparison result such that saturation of the flyback SMPS is reduced.