A new digital soft start circuit for parallel current mode DC-DC converter

This paper presents a new digital soft-start circuit for the parallel current mode dc-dc converter. It is required to operate in soft-start and in parallel for the energy saving. Since the optimal parameters for the soft-start change depending on the load condition, it is important to detect the load condition. In the conventional analog control circuit, the fixed large parameter of the soft-start circuit must be chosen for the worst condition. In the proposed digital control in the current mode control, the load resistor can be calculated with the output voltage and output current. Therefore, the dc-dc converter can operate in the optimal soft-start operation corresponding to the load condition. Additionally, the dc-dc converters operate in parallel to equip the redundancy then ensure the reliability. It is confirmed that the proposed digital control method has superior soft-start characteristics to conventional analog control method.