Improved transformer design for high frequency VRM applications

The desire for higher frequencies in VRM designs to reduce the size and number of passive components resulted in soft switching topologies that reduced the gate driving loss and body diode conduction loss at high frequencies. Many of these high frequency soft switching designs use step down transformers to reduce the circulating energy in the primary side components. The transformer design for these topologies is integral to their success do to its relation to ZVS conditions and body diode conduction losses. The magnetic improvements proposed reduce the leakage inductance of integrated transformers, the number of magnetic components required, and increase the overall efficiency of the design. The topology used in this work was the 1 MHz self-driven DC-DC converter for non-isolated 12V VRM.