J. Zarębski

The Electrothermal Large-Signal Model of Power MOS Transistors for SPICE

In this paper, the isothermal model of power MOS transistors offered by the producer of these devices and the electrothermal model of these devices proposed by the authors are presented. The results of experimental verification of both the models are given as well.

Nonlinear Compact Thermal Model of Power Semiconductor Devices

In this paper, the nonlinear compact thermal model of power semiconductor devices based on the Cauer network is proposed. The analytical description of the model and the method of the model parameter estimation are presented. The accuracy and usefulness of the model is verified experimentally for the selected metal-oxide-semiconductor (MOS) power transistor at its various cooling conditions.

Modeling Nonisothermal Characteristics of Switch-Mode Voltage Regulators

The paper concerns modeling the nonisothermal characteristics of switch-mode voltage regulators (VRs) consisting of the boost converter with discrete semiconductor devices and a monolithic current-mode pulsewidth modulation controller. New electrothermal hybrid models of a p-n diode and a power metal oxide semiconductor transistor, as well as the electrothermal model of the monolithic UC3842 controller dedicated for SPICE analysis of switch-mode VRs are presented and described in detail. The results of simulations verified experimentally are given as well.

A Method of Measuring the Transient Thermal Impedance of Monolithic Bipolar Switched Regulators

In the paper, a new electrical method of measuring the transient thermal impedance Z(t) of monolithic switched regulators with a bipolar junction transistor as a switch, is proposed. In the method, based on the cooling curve, the electrical power is dissipated in the considered device operating in the boost converter being their typical (catalogue) application circuit. As a thermally sensitive parameter, the voltage across the body diode is used. The general conception of the method is presented. As an example of the realization of the method, the measuring set for LT1073 operating in the boost converter is described and examined in detail. The correctness of the method was proved by means of the known (standard) electrical method and the infrared method, in the wide range of changes of the power dissipated in the investigated device as well as at various conditions of the device cooling.

The Method of a Fast Electrothermal Transient Analysis of Single-Inductance DC–DC Converters

In this paper, a new method for fast estimation of the characteristics of single-inductance dc-dc converters at the steady state with self-heating taken into account is proposed. This method is based on the special memoryless convolution algorithm. The method is described in detail. The theoretical considerations are illustrated with simulation results of buck and boost converters.

Electrothermal analysis of the self-excited push―pull DC―DC converter

Abstract The SPICE-aided electrothermal analysis of a self-excited push–pull DC–DC converter is considered in the paper. The new electrothermal model of a pulse transformer, which constitutes the basic component element of the considered converter, is proposed. This model contains among others: two different temperatures of the windings and the core, the influence of temperature on losses in the core and in the windings, the dependence of the magnetization curve on the core temperature, the Curie temperature, selfheating and mutual thermal interactions between the core and the windings. The semiconductor devices are described with the use of the hybrid electrothermal models. The measurements and electrothermal calculations of the characteristics of the investigated converter with the use of the models proposed in the paper are performed. A good agreement between the results of the calculations and the measurements achieved with this model testifies to correctness of the presented models.

Spice-aided modelling of the UC3842 current mode PWM controller with selfheating taken into account

This paper deals with the problem of modelling current mode PWM controllers with the use of SPICE. The monolithic integrated circuit UC3842 is considered in the paper. Two isothermal models of UC3842 known in the literature are compared, tested and discussed. A new electrothermal model (ETM), including selfheating, of the considered controller is proposed and described in detail. The experimental verification of the ETM showed its much greater accuracy compared to the isothermal models of the investigated device.

Modeling the Influence of Selected Factors on Thermal Resistance of Semiconductor Devices

In this paper, the analytical description of the nonlinear thermal model of the semiconductor device considering the influence of the selected factors on its thermal resistance is proposed. The worked out nonlinear thermal model considers the influence of such factors as length of metal leads, solder area, dimensions of the heat-sink, ambient temperature, and dissipated power on the efficiency of heat transfer between the chip and the surrounding. The correctness of the worked out thermal model is verified experimentally for the selected types of semiconductor devices operating in different cooling conditions. In all the considered cases, the good agreement of the results of calculations and measurements is obtained.

Parameter estimation of the electrothermal model of the ferromagnetic core

The paper presents a form of the electrothermal model of the ferromagnetic core for SPICE and the way, in which parameters of the model are determined. The manner of determining magnetic, geometric and thermal parameters of this model is described. The correctness of the proposed model and the manner of determining the values of parameters are verified by comparing the calculated and measured characteristics of the selected ferromagnetic cores.

The electrothermal macromodel of the monolithic voltage regulator LT1073 for SPICE

In this paper the problem of modelling selfheating influence on the characteristics of monolithic switch-mode power supplies is considered. The LT1073 integrated circuit (IC) has been chosen for detailed investigations. Its new ElectroThermal Macromodel (ETM) joining the Electrical Model (EM) along with the thermally dependent parameters and the Lumped Thermal Model (LTM) generating the junction (inner) temperature of LT1073 is proposed. The correctness and usefulness of the new model has been revealed by means of comparison of measurements and simulations of BOOST converter including LT1073 device.