A two stage voltage regulator module with fast transient response capability

Multiphase converters based on buck topology are very good candidates for voltage regulator modules that convert from 5 V or 12 V down to 1.5 V. However, their applicability is very restricted at higher input voltages (24 V, 48 V). In those applications where a fast dynamic on-board DC/DC converter with a high input voltage (24 V, 48 V) is required, interleaved buck topology can still be useful if a "DC/DC current transformer" is used to adapt the voltage and current levels, providing a symmetric operation (around 50% duty cycle) to the multiphase converter. A "two phases synchronous buck + current fed push pull (50%)" prototype is tested to validate the concept in a 24 V to 1 V-50 A converter with a fast transient response capability (20 A/gs). Measured efficiency is 84% at 1 V, 50 A (91% at 25 A). The proposed solution is compared with other candidates for the same specifications: "single stage half bridge" converter, "two-phases half bridge" converter and "three-phases half bridge" converter.