Traditionally SPICE simulations have been extensively used to validate switched mode power supply designs. It takes multiple iterations of each simulation type at a design corner and there are multiple such simulations required over several design corners to find and fix issues, which is tedious and error prone. This paper presents a novel methodology of using detailed analytical circuit equations in addition to simulations for automated validation of power supply design. In this work we propose automatic detection and correction of design issues over required design corners. This significantly reduces the number of simulations required for design sign-off and therefore drastically reduces overall design cycle time. This paper demonstrates the effectiveness of proposed approach for design validation of power supply using a step down DC-DC converter.