Average modeling and analysis of a Flyback with Active Clamp topology based on a very simple transformer

This paper presents the average model and analyzes the dynamics of a low power (10W) topology derived from Flyback with Active Clamp based on very simple and low cost transformers. The main feature of this Flyback topology is that the ratio between magnetizing inductance and the series inductance (leakage or integrated inductor) is very low (around 10/1). Operation of the topology is analyzed. The relationship between variables allows for reducing the order of the large signal average model. The average model is validated in a prototype (VIN =42V, VOUT = 3.3V, IOUT = 5A). The proposed solution, presented in [1], achieves a promising trade-off between efficiency and cost in low power applications with medium or high input/output voltage ratio.