Analysis of Output Voltage Ripple of Buck DC-DC converter and its design

The operating region of the converter is divided into four parts on the input-voltage versus load plane according to the inductance. The Maximum Output Voltage Ripple (MOVR) in each operating region is analyzed, respectively. It is pointed out that the minimum inductance to guarantee the lowest Output Voltage Ripple (OVR) is the critical inductance of CCM and DCM under the highest input voltage and heaviest load. The design method of inductance and capacitance is proposed according to the requirement of intrinsic safety and the desired OVR level within the total operating range. The analysis and feasibility of the proposed method are verified by the experiment results.