Patent ID: 7251113

Claim:
A direct current to direct current (DC-to-DC) converter having an improved fast transient response, the converter comprising: a DC-to-DC main converter having an input terminal and a DC output terminal with a first and second capacitor connected across the output terminal; and an active transient voltage compensator (ATVC) connected in parallel with the output terminal between the first and second capacitor, the active transient voltage compensator comprising: a transformer having a primary winding and a secondary winding, one end of the secondary winding connected to one end of the first capacitor to provide a stepped inductance during the transient operation to compensate the output voltage while maintaining normal inductance during the steady state operation; a switching circuit having a step-up synchronous rectifier and a step-down synchronous rectifier connected with one end of the transformer primary for controlling a transformer current, the other end of the primary and secondary connected to one end of the second capacitor; and an ATVC controller connected to the ATVC for monitoring the output voltage and producing a driver signal for activating one of the step-up and step-down synchronous rectifiers to inject a voltage source to compensate the output voltage when the output voltage falls below an ATVC reference voltage and increases above the reference voltage, respectively, to compensate the DC output terminal output voltage during a transient operation without switching loss during a steady-state operation.