Developing electro-thermal models using VHDL-AMS is a new approach to solve problems that were found in the development of different systems. One of these systems can be a DC DC converter, which is the one that has been studied and presented now. A study of the distribution of power consumption which is the problem considered has been developed, considering the devices that present the higher power consumption percentage. The ma or part of the electrical thermal models are constructed using VHDL-AMS (analogue mixed signal) modelling language. VHDL-AMS is an extension of VHDL, which is a system level modelling language known as the 176.1-1 standard.