Loop Closing of Flyback Switching Power Supply Using Capacitive Coupling

This article demonstrates the functionality of a switching power supply employing the flyback topology with a capacitive closed control loop. The laboratory implementation of the Switched Mode Power Supply (SMPS) is presented, highlighting the importance of capacitive coupling for achieving efficient power transfer while maintaining necessary isolation and safety between interconnected modules. To showcase the operational capabilities of the switching power supply, an illustrative and experimental module has been developed, employing capacitive coupling to establish the feedback loop. The use of the flyback topology ensures galvanic separation, enhancing the overall performance of the system. The module is structured into two main components: the primary module and the secondary module. Experimental determinations encompass various aspects, including the testing of capacitive coupling using an AB class amplifier driver. Additionally, the delay times for both optical and capacitive couplings are determined through experimentation. The rise time and fall time between the capacitive coupling and the optical coupling are also examined. The results of these experiments shed light on the advantages and limitations of capacitive coupling compared to optical coupling in the context of the switching power supply. The findings presented in this article contribute to a comprehensive understanding of the benefits and performance characteristics associated with capacitive coupling and optical coupling in practice.