The power-supply sequence timing requirements of TMS320DM644x SoC and the main features of the buck DC-DC converter TPS54310 are presented. There is the circuit design, simulation and verification of the power supply based on TPS54310 for TMS320DM644x SoC through the theoretical analysis. The results show that the power supply has the advantages of high conversion efficiency, low power consumption, the stable and accurate output voltage, low ripple, etc. The TPS54310 output voltages are monitored in real time by the supervisory chip TPS3808G01, which ensures the proper power-on sequence and reset, and makes the system operate stably and reliably. It can provide the beneficial reference for other SoC power supply systems.