1.8MHz isolated DC-DC converter with multitransformer structure for automotive applications

This paper discusses a MHz isolated HV/LV DC-DC converter for automotive applications. The proposed circuit is constructed with a low cost structure by using multitransformer and Si-MOSFETs to achieve frequency multiplying. Three circuit configurations namely, cascaded-type, parallel-type and cascaded-parallel-type, are considered and discussed. Fundamental control and switching behaviors are explained. A prototype based on cascaded-parallel-type was constructed to verify the validity of control theory. The experimental results show that 84% efficiency is achieved at 1.8MHz, and FFT analysis of the common mode current was evaluated to show the effectiveness of the proposed technique.