A High-Efficiency Switching Oscillation Suppression Strategy Based on Damped Oscillation for Synchronous DC-DC Converter

This paper proposes a high-efficiency strategy to suppress the switching-point oscillation by changing the state of the damping response. The detailed analysis is based on a synchronous rectification buck topology. In the new strategy, an additional MOSFET in a small package parallels the upper MOSFET. At the moment of turn-on of the additional MOSFET, an external resistor is introduced to increase the branch impedance and suppress oscillation. Thus, the equivalent dead time can be reduced to nearly zero while the switching safety is still ensured, and the reverse recovery of the body diode can also be reduced. As a result, this strategy allows the selection of MOSFETs with lower breakdown voltage and smaller parasitic parameters and further improves the performance of the converter. After detailed theoretical analysis, experimental results are presented to verify the effectiveness of the proposed strategy.