Design Tradeoffs of A DC-DC Buck-Boost Converter Employing An RCD Snubber

The RCD (resistor-capacitor-diode) snubber is typically used in low-power applications to limit the maximum voltage stress across the semiconductor during turn off, although power dissipation occurs in the resistor with consequent reduction of efficiency. Even though it may not be an adequate solution for high power levels, it is still widely employed instead of soft switching circuits due to inherent simplicity. This work presents an optimized and practical step-by-step design procedure for an RCD snubber applied to a dc-dc buck-boost converter, which is not found in power electronics-related books. It is effectively shown how it is possible to design the snubber and the converter while maintaining acceptable voltage stresses across the switches with reduced losses. An experimental prototype is developed, as it is possible to validate the theoretical analysis properly.