Study Of Voltage Regulator Module (VRM)

High-density and high-effiency are the characteristics of voltage regulator modules(VRMs), but with the higher demand of IC power supply, the 5V or 12V input VRMs are not suit for the situation, and it can be concluded that the VRM's input voltage must be increased to 48V in the future, and it can decrease the dissipation of the modules, also can decrease the volume of the input-filter.In this paper, 48V in and 3.3V/30A out VRM is the main study object, and the active-clamp forward topology is chosen. First, the detail operation principle and loss estimation of the active-clamp forward converter is introduced. Next, the design principle of the active-clamp forward is presented. Next, the small signal model of this topology is presented, and the design consideration of the control loop is stated. At the last, the experiment results of a 48V in and 3.3V/30A out prototype are presented.