A synchronous DC-DC converter for converting an input voltage (V in) into an output voltage (V out), the converter configured to have a continuous current operative mode and a discontinuous current operative mode, the converter including: an active switch configured to receive a first gate signal for turning on the active switch for a first time interval (T q1), the first gate signal having a period (T prd); a synchronous rectifier configured to receive a second gate signal for turning on the synchronous rectifier for a second time interval (T q2); and a controller configured to determine an estimation (T q1est) for the first time interval (T q1), and thereafter compare the estimation (T q1est) with the value of the first time interval (T q1); wherein responsive to the comparison the controller is configured to determine an operative mode of the converter and control the second time interval (T q2) depending on the determined operative mode, and wherein comparing the estimation (T q1est) with the value of the first time interval (T q1) involves increasing the estimation by an amount (deltaT) attributable to an estimation of losses in the converter and comparing the value of the first time interval (T q1) with the increased estimation, and characterized in that the converter further includes: means for sensing a value of voltage (V sw) across the synchronous rectifier and wherein if the controller determines the operative mode as discontinuous current operative mode the second time interval (T q2) is adjusted according to the sensed voltage value (V sw), whereby: in the case of a buck converter, adjusting the second time interval (T q2) includes increasing the second time interval (T q2) if the sensed voltage value (V sw) has a negative polarity, and adjusting the second time interval (T q2) includes decreasing the second time interval (T q2) if the sensed voltage value (V sw) has a positive polarity, or in the case of a boost converter, adjusting the second time interval (T q2) includes increasing the second time interval (T q2) if the sensed voltage value (V sw) exceeds the output voltage (V out), and adjusting the second time interval (T q2) includes decreasing the second time interval (T q2) if the sensed voltage value (V sw) is less than the output voltage (V out). an active switch configured to receive a first gate signal for turning on the active switch for a first time interval (T q1), the first gate signal having a period (T prd); a synchronous rectifier configured to receive a second gate signal for turning on the synchronous rectifier for a second time interval (T q2); and a controller configured to determine an estimation (T q1est) for the first time interval (T q1), and thereafter compare the estimation (T q1est) with the value of the first time interval (T q1); wherein responsive to the comparison the controller is configured to determine an operative mode of the converter and control the second time interval (T q2) depending on the determined operative mode, and wherein comparing the estimation (T q1est) with the value of the first time interval (T q1) involves increasing the estimation by an amount (deltaT) attributable to an estimation of losses in the converter and comparing the value of the first time interval (T q1) with the increased estimation, and characterized in that the converter further includes: means for sensing a value of voltage (V sw) across the synchronous rectifier and wherein if the controller determines the operative mode as discontinuous current operative mode the second time interval (T q2) is adjusted according to the sensed voltage value (V sw), whereby: in the case of a buck converter, adjusting the second time interval (T q2) includes increasing the second time interval (T q2) if the sensed voltage value (V sw) has a negative polarity, and adjusting the second time interval (T q2) includes decreasing the second time interval (T q2) if the sensed voltage value (V sw) has a positive polarity, or in the case of a boost converter, adjusting the second time interval (T q2) includes increasing the second time interval (T q2) if the sensed voltage value (V sw) exceeds the output voltage (V out), and adjusting the second time interval (T q2) includes decreasing the second time interval (T q2) if the sensed voltage value (V sw) is less than the output voltage (V out). means for sensing a value of voltage (V sw) across the synchronous rectifier and wherein if the controller determines the operative mode as discontinuous current operative mode the second time interval (T q2) is adjusted according to the sensed voltage value (V sw), whereby: in the case of a buck converter, adjusting the second time interval (T q2) includes increasing the second time interval (T q2) if the sensed voltage value (V sw) has a negative polarity, and adjusting the second time interval (T q2) includes decreasing the second time interval (T q2) if the sensed voltage value (V sw) has a positive polarity, or in the case of a boost converter, adjusting the second time interval (T q2) includes increasing the second time interval (T q2) if the sensed voltage value (V sw) exceeds the output voltage (V out), and adjusting the second time interval (T q2) includes decreasing the second time interval (T q2) if the sensed voltage value (V sw) is less than the output voltage (V out).