A Non-Isolated Dual-Output High-Step-Down Converter

Abstract

The AC-DC converter for general communication and network communication equipment can generate 48V DC bus. The traditional buck converter directly generates an output voltage less than 3.3V DC from a 48V DC bus with PWM duty cycle being under 10%, which often causes problems in controller design difficulties and high switching losses. In a real digital circuit system, different digital chips usually require different operating voltages, and this means that multiple voltage rails of the power supply are required. This paper proposes a dual-output high-step-down converter, which consists of 6 actives switches. The proposed topology has the following three advantages: (1) zero voltage switching technology can improve conversion efficiency. (2) the buck-type voltage gain doesn't have non-linear component, and therefore the existing buck controller IC can be used. (3) multiple output voltages can be controlled by a single controller. (4) it may be extended to more than 2 output rails.