A direct current to direct current (DC-to-DC) converter having an active transient voltage compensator (ATVC) coupled with the DC-to-DC converter output terminal to improve a fast transient response of the DC-to-DC converter. The active transient voltage compensator compensates the DC output only during transient operation The ATVC includes a transformer for reducing the ATVC current stresses to improve the compensator efficiency and injecting, absorbing high slew rate current, and a controller circuit for controlling ATVC operation in steady state and normal operation in transients. During step-up load the ATVC operates as a buck converter and during step-down load, the ATVC operates as a boost converter while the main converter operates at low switching frequency for good efficiency.