Category | Thermal Management

Factors Influencing Thermal Resistance of Power Modules

Posted on 28 December 2020

    This article describes various influences on the thermal resistance of power semiconductor devices. For an overview of heat transfer mechanisms, refer to the article "Heat Transfer in Power Semiconductor Devices".     Number of heat sources The number of heat sources spread across the heatsink has a crucial impact on Rth(s-a). Unless explicitly [...]

Heat Dissipation and Thermal Resistance in Power Modules

Posted on 26 December 2020

              In order to utilize the theoretical current capability as much as possible, power losses have to be optimally conducted through the connection layers - and for modules also through the insulation layers - to the heat sink. The quality of dissipation for the heat losses Ptot generated during [...]

Thermal Impedance and Thermal Resistance

Posted on 19 December 2020

              Thermal impedance is defined as a quotient of the time function of a temperature difference divided by the impressed power dissipation. In the datasheets this value is given as a function of time in the form of a diagram. Z_{th}(t) = \frac {T_1(t) - T_2(t)}{P} The static upper [...]

Comparison of Power Modules with or without a Base Plate

Posted on 17 December 2020

  Some comparisons of power modules with or without a baseplate are rather inaccurate since they compare the two technologies by examining a module with base plate to begin with and then simply removing the base plate to perform the comparison. Of course, both design variants must be constructed by totally different methods. Both technologies [...]

Cooling Methods for Power Semiconductor Devices

Posted on 13 December 2020

              Cooling methods can be classified according to the mechanism or medium used to transfer the heat during the cooling process. A commonly used method of cooling power semiconductors is air cooling, which includes natural air cooling and forced air cooling. Another type of cooling is liquid cooling. Liquid [...]

Heat Transfer in Power Semiconductor Devices

Posted on 20 November 2020

    Semiconductors generate heat during use. This heat must be removed in order to prevent further heating and consequent destruction of the semiconductor. Cooling is therefore key to the reliability of any given semiconductor. This article describes the nature of heat transfer as it applies to power semiconductor devices.   The smaller the temperature [...]

Measurement of Thermal Paste

Posted on 25 June 2020

              How to correctly measure the thickness of thermal paste Put the Wet Film Thickness Gauge vertically on the surface of the thermal paste without moving it horizontally. Press slightly and remove. Visually inspect the marks on the thickness gauge. The thickness of the thermal paste is between the [...]

Temperature Influence on Series Capacitance

Posted on 22 June 2020

  The capacitance of an electrolytic capacitor is not a constant quantity that retains its value under all operating conditions. Temperature has a considerable effect on capacitance. With decreasing temperature, the viscosity of the electrolyte increases, thus reducing its conductivity. Figure 1: Heat transport in a aluminum electrolytic capacitor             [...]

Liquid Cooling Systems

Posted on 19 June 2020

              In liquid cooling systems, the most commonly used heat transfer medium is water or a mixture of water and anti-freeze.  Occasionally, electrical insulation oil is used in cooling systems. When water is used in a cooling system, the water either forms a closed circuit and is air-cooled by [...]

Cooling Low Power Components

Posted on 11 June 2020

              With low power semiconductor components, the case surface and the terminals are normally sufficient to dissipate heat losses. The tracks on the printed circuit board (PCB) that are used to solder the connections can also play a big role in dissipating heat losses. For this reason, the junction [...]