This paper presents a reference modification model digitally controlled dc-dc converter. The proposed method is able to obtain superior transient response because it modifies a reference of conventional feedback loop against the change of output voltage. The modifying process operates only in the transient state. During the steady state, the feedforward control cancels a steady-state-error. Since the feedforward control uses the load current value, this paper discusses two current-sensing methods. One is the output current-sensing method using the sensing resistor, and the reactor current-sensing method using the R-C filter is discussed in order to reduce a performance loss by the sensing resistor. As a result, the output current-sensing method is effective in case that high-transient-response performance is required. On the other hand, it is better to use the reactor current-sensing method when efficiency is important.