Optimization-based tool to reduce the surface temperature in electronic circuits with transistors BJTs and MOSFETs in dangerous scenarios

Abstract

Improper use of electronic equipment in areas with a high risk of explosion is one of the main causes of deaths and property damages in the industry. The objective of this work is to establish an optimal operating point that improves the performance of electronic circuits using BJT or MOSFET technology transistors that feed a load in dangerous scenarios. For this, non-linear convex optimization is applied to the characterization of the thermal behavior of MOSFETs and BJTs in applications with a high risk of explosion. In this problem, the current in the transistor is used as a decision variable and the limit temperature on the surface of the electrical elements that generates autoignition of gases, dusts, combustible fibers, or other highly flammable products stored in classified enclosures as dangerous. This control variable allows working in different temperature categories, considering the classification of thermal risk levels standardized by the fire safety industry. In addition, transistors that keep the nominal current given by the manufacturer as the maximum restriction were considered. With this, it is possible to obtain an adequate working point that allows determining the optimal values of the thermal behavior equations for specific models of MOSFETs and BJTs commonly used in industrial applications. In the mathematical analysis, the Karush Kuhn Tucker (KKT) method is used to solve the proposed problem and obtain the optimal solutions for the different scenarios considered. Based on these mathematical solutions, an algorithm is proposed to solve the general problem of minimizing the surface temperature quickly and efficiently in transistors by controlling the current in the transistors. With this optimization analysis, it is possible to determine a safe thermal operating point for the device that is operating in an installation classified as hazardous and at the same time maintaining the required levels of voltage and current for the load or signal that needs to be fed or amplified respectively.