This study presents a sensorless static model based with output current estimation method for digital PWM control dc-dc converters. The static model is a feedforward type control method adopted in coordination with the standard PID control and it can improve characteristics of wide input and output range of dc-dc converter by using information of output current. The one of the drawbacks of the static model is that it requires an additional sensing circuitry of output current and it causes the power loss for sensing, increase of cost and computation burden. In the presented method, the output current required to adopt the static model is obtained from the estimation with the static equation of the on-time duration. Since the estimation uses the calculated on-time duration, the estimated results tend to oscillate and it also causes the oscillation of the output voltage. Therefore, a simple filter function is adopted to obtain smooth estimation results. By this filtering, such oscillation is avoided and the superior characteristics is maintained. In this article, the analytical results of stability are obtained to design the filter function when whole converter and controller are modelled with the continuous averaging method. The digital controller is implemented by using these analytical results. Evaluation results show that the effectiveness of the presented method both in transient and steady states when a buck-type dc-dc converter is used as a case study.