Adaptive Voltage Positioning Design of Single Stage 48/1V Sigma Converter for Fast Transient Response

48V voltage regulator modules (VRMs) are critical for telecom power supplies and are becoming popular for future data centers. By using a novel sigma converter topology, an outstanding performance in terms of efficiency (95%) and power density (700 W/in
³
) have been demonstrated. However, the control of the Sigma converter is challenging due to the quasi-parallel structure and has not been solved properly yet. In this paper, a control method combining V
²
control and active droop control is adopted for the Sigma converter. A design guideline is proposed to achieve adaptive voltage positioning (AVP). Following the proposed design guideline, simulation and experimental results demonstrate good transient responses.