Dynamic Droop Scaling for Improving Current Sharing Performance in a System with Multiple Supplies

A novel dynamic droop scaling (DDS) technique is proposed to improve current sharing performance of multiple supplies system. Owing to the implementation dual current sensing loops, the power dissipation of sensing resistor can be reduced compared with conventional droop technique. Besides, the dual current sensing loops not only increase droop slope but also eliminate the requirement of expensive and accurate external components. Furthermore, the proposed incremental output voltage circuit can raise output voltage to meet the requirement of allowable minimum output voltage according to increment of load current. It means that the DDS can break through the limitation of conventional droop technique. A system supplied by two supply modules with rated 20A output current demonstrates the correction of our DDS technique. The current difference between two supply modules can be shrunk from 12.5A to 2.9A. In other words, the error percentage of current sharing performance can be improved from 42.5% to 8.2%.