A Two-Phase Resonant Switched-Capacitor Converters Using PCB Trace Integration

The resonant switched-capacitor converters have been demonstrated to avoid capacitor current spike and achieve soft switching, to have high reliability and high efficiency. However, the power density is reduced due to the presence of discrete resonant inductors. To address the issue, this work presents an integration method of resonant inductors for the two-phase resonant switched-capacitor converters by using PCB copper traces. The proposed integration method is based on the direct coupling theory, in which the PCB trace coupling of two resonant switched-capacitor converters in phase can reduce the PCB trace length and copper loss. More importantly, the core loss of discrete inductors can be eliminated. This proposed method can not only improve the light-load efficiency and power density, but also reduce the cost of the discrete inductors. Two 240W GaN-based experiment prototypes based on discrete inductors and proposed integrated PCB trace inductors are tested and compared to validate the effectiveness of the proposed integration method. Experimental results demonstrate that the prototype with PCB trace inductors can achieve higher light-load efficiency and power density.