Comparison of two 12 V voltage regulator module topologies

In order to meet the demands for faster and more efficient data processing, modern microprocessors are being designed with lower supply voltages. The processor voltage supply, as specified in the Intel VRM 9.1 specification, should be in the range of 1.1 V to 1.8 V, and it is anticipated that the supply voltage will drop further in the coming years. As more devices are packed onto a single chip the current demands of the microprocessor will also increase. Additionally, the input voltage of the new generation of dc/dc converters is being increased to 12 V, to reduce resistive distribution losses. These demands will require special power supplies, known as VRMs, to provide lower voltages with higher currents and fast transient capabilities for microprocessors. This paper is concerned with the investigation into topologies capable of meeting future VRM requirements. Two such topologies, the winding-coupled buck converter and the improved push-pull forward converter, are identified and their relative merits under a number of headings are compared. The optimum topology for VRM applications, based on the findings of this work, is then identified.