Digital Pulse Width Modulation (DPWM) is one of the most elementary parts in Digital Control Systems for the control of the power switch. Hence it has become an integral part of all System on Chips. It has also been broadly acknowledged as the control method in power converters. The principal focus of this paper is the design of FPGA based Digital controller for a DC-DC Buck convertor for SoC. The output voltage of a DC-DC convertor relies on the switching control circuit which is fundamentally an FPGA Digital controller-PWM. VHDL is employed for the coding of the Digital Controller, synthesis has been done using Xilinx XST 14.2, and Behavioral and Timing simulation has been handled by ModelSim. Also a power analysis using the XPower Analyzer is being carried out. After verification of the code, it will be downloaded onto a Spartan 3AN FPGA board.