Four-phase Buck Converter Design and Thermal Modeling Using FEA Simulation

Equipment with high efficiency, high power density, reduced size and low cost are in demand in the automotive industry. This work presents a method to design and model a high power-density four-phase DC-DC Buck converter for an automotive application and using the components operating temperature as a design criteria. A parameter sweep is done to select the operating point of the DC-DC converter combined with an iterative method to select part numbers, where preference is given to components that are AEC-Qxxx qualified. The converter is modeled and power losses are computed in SPICE considering the parasitic elements present in the PCB and the dynamic characteristics and non-idealities of the electronic components; thermal modeling is performed using Ansys Icepak. The results indicate that the design meets all electrical and thermal requirements for an automotive application. An efficiency of 95.97% is obtained in a four-phase DC-DC Buck converter that supplies a total of 800 W to 4 loads, in a space of 43.77 cm
³
, that is, an estimated power density of 18.28 W/cm
³
.