This paper will deal with the modeling-problem of combining thermal subsystems (e.g. a semiconductor module or package with a cooling radiator) making use of reduced models. The subsystem models ...consist of a set of Foster-type thermal equivalent circuits, which are only behavioral models. A fast algorithm is presented for transforming the Foster-type circuits in Cauer-circuits which have physical behavior and therefore allow for the construction of the thermal model of the complete system. Then the set of Cauer-circuits for the complete system is transformed back into Foster-circuits to give a simple mathematical representation and applicability. The transformation algorithms are derived in concise form by use of recursive relations. The method is exemplified by modeling and measurements on a single chip IGBT package mounted on a closed water cooled radiator. The thermal impedance of the complete system is constructed from the impedances of the subsystems, IGBT-package and radiator, and also the impedance of the package can be inferred from the measured impedance of the complete system.
Power MOSFETs with a current capability of up to several thousand amperes and hence an active device area significantly exceeding the typical IC chip size can be realized only if a wafer repair ...technique is used. A suitable technique has been developed and used to realize circular power MOSFETs with a diameter of 3 cm. The devices are suited to control up to 2000-A drain current and exhibit an on-resistance of R/sub DS(on)/=0.9 m Omega . To contact such a device, a pressure contact system adequate to the high-current value is used. Typical switching times are about 100 ns. Such a large-area MOSFET was used in a MOSFET-GTO (gate turnoff thyristor) cascode circuit to switch anode currents up to 1200 A/1000 V. The total switching time was significantly reduced, and a smaller snubber capacitor could be employed than with the GTO in a conventional circuit.< >
Due to the dissipated power and the thermal impedance of the package, power devices like the IGBT are subject to significant temperature stress. This paper describes the behaviour of an IGBT within ...an electrical circuit, at a critical switching condition-the dynamic short. The dissipated electrical power and the resulting temperature rise are analyzed in order to get an insight into the device behaviour close to destruction. Our goal was to evaluate the simulated results in terms of the device temperature to get information about the maximum time the device can survive within this mode of operation.
This paper deals with the modeling problem of combining thermal subsystems (e.g. a semiconductor module or package with a cooling radiator) making use of reduced models. The subsystem models consist ...of a set of Foster-type thermal equivalent circuits, which are only behavioral models. Fast algorithms are presented in concise form by use of recursive relations for transforming (in both directions) unphysical Foster-type circuits in Cauer-circuits, which have physical behavior and therefore allow for the construction of the thermal model of the complete system. The R, C elements in the circuit can have negative values contrary to conventional network theory. Therefore the transformation methods have to be investigated under relaxed conditions concerning positive realness and passivity of the impedances. The method is exemplified by modeling and measurements on a single-chip IGBT package mounted on a closed water-cooled radiator. The thermal impedance of the complete system is constructed from the impedances of the subsystems, IGBT-package and radiator, and also the impedance of the package can be inferred from the measured impedance of the complete system. For modules or packages with large thermal contact area of largely inhomogeneous temperature a multi-port description is presented, which can be viewed as an extended two-port theory. In case of real two-ports the presented recursive analytic calculation methods for the impedances/admittances give an easy-to-use description for high calculation speed for all boundary conditions of the Cauer-network.
The development of power supply technology has always been associated with the need for further miniaturization. This means that power semiconductors must be mounted at short distances on the same ...heat sink. Adjacent power semiconductors have an increasing influence on the chip temperature. The maximum junction temperatures, which are specified by the manufacturer under all operating conditions, may not be exceeded. As a rule, the chip temperatures are calculated on the basis of the losses and thermal impedance of a power semiconductor according to manufacturer's specifications. The following paper presents a procedure for determining the junction temperatures of power semiconductors in switch-mode power supplies, considering common heat-sink and arbitrary power-loss functions.
In the European funded project E3Car (ENIAC) the available power module technologies for Electric Vehicles (EV) are evaluated and tested. Up to now there are some automotive qualified power modules ...mostly for Hybrid electric vehicle applications on the market with rated blocking voltage up to 600V. But there are almost no 1200V automotive power modules available. This paper describes the optimization of an industrial power module by using the Finite-Elements-Method (FEM) for an improved thermal management. Starting with existing industrial power modules in this paper the baseplate design was investigated in general with simulations and thermal measurements. Then the baseplate thickness was varied in simulation in order to get a thermal optimum due to e.g. heatspreading. Then power modules with optimized baseplate design were realized and thermally investigated. Finally power cycling tests have shown that the lifetime compared to an original industrial power module was almost doubled.
This paper will deal with the modeling-problem of combining thermal subsystems (e.g. a semiconductor module or package with a cooling radiator) making use of reduced models. The subsystem models ...consist of a set of Foster-type thermal equivalent circuits, which are only behavioral models. A fast al-gorithm is presented for transforming the Foster-type circuits in Cauer-circuits which have physical behavior and therefore allow for the construction of the thermal model of the complete system. Then the set of Cauer-circuits for the complete system is transformed back into Foster-circuits to give a simple mathematical representation and applicability. The transfor-mation algorithms are derived in concise form by use of recur-sive relations. The method is exemplified by modeling and measurements on a single chip IGBT package mounted on a closed water cooled radiator. The thermal impedance of the complete system is constructed from the impedances of the sub-systems, IGBT-package and radiator, and also the impedance of the package can be inferred from the measured impedance of the complete system.
Power MOSFETs with a current capability of up to several thousand amperes and hence an active device area significantly exceeding the typical IC chip size can be realized only if a wafer repair ...technique is used. A suitable technique has been developed and used to realize circular power MOSFETs with a diameter of 3 cm. The devices are suited to control up to 2000-A drain current and exhibit an on-resistance of < e1 > R < /e1 > (DS(on))=0.9 mOmega. To contact such a device, a pressure contact system adequate to the high-current value is used. Typical switching times are about 100 ns. Such a large-area MOSFET was used in a MOSFET-GTO (gate turnoff thyristor) cascode circuit to switch anode currents up to 1200 A/1000 V. The total switching time was significantly reduced, and a smaller snubber capacitor could be employed than with the GTO in a conventional circuit
A new 1200 V-IGBT chip is presented which has an optimized planar cell structure for lowest on-state voltage, but that nevertheless guarantees a very high degree of ruggedness. The key point for ...these features is a new self aligned process concept with a double implanted submicron emitter structure, which will be the basis also for a lower voltage IGBT (600 V) as well as for high voltage IGBTs (1600 V and higher).
