EPE Association: EPE 1993 - 27 - Dialogue Session DS1.3: DEVICES: THERMAL EFFECTS

EPE 1993 - 27 - Dialogue Session DS1.3: DEVICES: THERMAL EFFECTS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1993 - Conference > EPE 1993 - 27 - Dialogue Session DS1.3: DEVICES: THERMAL EFFECTS

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   DISSIPATION IN POWER SEMICONDUCTOR DEVICES - THE DEVELOPMENT OF THE MAGIC OF i(1+n). Pt. 1
By V. L. Shper [View]
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Abstract: This work presents the development of Newell's approach to analysis of current capacity of power semiconductor devices. The steady-state average temperature rise for repetitive current waveforms and temperature excursions from a single surge are discussed in detail. New relationships that permit the user to evaluate the current capacity of the devices without knowing the current-voltage characteristics and thermal resistance are derived. For the surge currents the results presented permit the sinusoidal or cosinusoidal pulse to be replaced by equivalent rectangular one for which all necessary calculations can be easily made. The technique of temperature calculation during device cooling after current pulse is defined more precisely than in previous publications and real examples are given.

   TRANSIENT THERMAL EFFECTS DURING TURN OFF IN GTO DEVICES
By P. A. Mawby; M. S. Towers; M. Evans; Z. Hu; K. Board [View]
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Abstract: A rigorous two-dimensional physical model of the GTO thyristor is presented. The model includes the fully coupled effects of self heating of the device during the turn-off phase of operation. The effects of spatially dependent minority carrier lifetime, Auger recombination and carrier-carrier scattering are included in the model. The simulation can be carried out within a realistic external circuit environment.

   A CORRECTION OF MEASURED POWER MOSFET's NORMALIZED TEMPERATURE RESPONSE BECAUSE OF A CASE TEMPERATURE RISE
By Z. Jakopovic; Z. Bencic; R. Zunac [View]
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Abstract: A method of power MOSFET's normalized temperature response (transient thermal impedance) measurement and correction is presented. During semiconductor device's normalized temperature response measurement it is practically impossible to maintain constant case temperature required by a definition of normalized temperature response. Introduced method enables a correction of the measurement error caused by the semiconductor device's case temperature rise. It is based on finding semiconductor device's thermal system model parameters and identifying the point on thermal model which belongs to semiconductor device's case. Measurements of power MOSFET's normalized temperature response are made with a help of a computer controlled electrical method, with semiconductor device mounted on a real heatsink. A developed software package enables: (i) graphical presentation of temperature responses, (ii) identification of semiconductor device thermal system parameters and (iii) correction of measurement error caused by semiconductor device's case temperature rise.

   PARALLELING OF SEMICONDUCTORS INCLUDING TEMPERATURE FEEDBACK, USING SPREADSHEET OR SIMULATION TOOL, TO CALCULATE CURRENT AND TEMPERATURE DIFFERENCES
By Terje Rogne; Olve Mo; Manfred Schlürscheid [View]
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Abstract: Paralleling of semiconductors like IGBTs and diodes is complicated due to the usually negative temperature coefficient of forward voltage drop, and positive temperature coefficient of switching losses. This paper states which component knowledge is necessary as input and then presents two efficient tools for calculating the current and temperature differences of the paralleled semiconductor chips. When using either of the two tools, a spreadsheet or circuit simulation programme, the feedback from the temperature is included through iterations. lt is shown that for instance a 20% imbalance in voltage drop and switching loss may demand a derating down to 32% in a typical chopper application at 20 kHz. With a sinusoidal current, as in a motor inverter, with 20% imbalance, a derating down to 69% is sufficient. Large switching versus conduction losses are very bad when parallelling typical bipolar semiconductors. When parallelling, it is optimal with a faster semiconductor, or a lower frequency, compared to when using one single switch. This paper also gives measured data for various lGBTs, and pictures of measured current sharing between paralleled IGBTs.

   THERMAL MODELING FOR ELECTROTHERMAL SIMULATION OF POWER DEVICES OR CIRCUITS
By P. Tounsi; J.-M. Dorkel; Ph. Leturcq [View]
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Abstract: To perform electro-thermal simulation of power devices or circuits, the authors have developed specific thermal simulation tools which only require limited computational time and effort. 3D and transient flow spreading effects in multilayered substrates commonly used in power component packaging as well as in hybrid power circuits are considered. The paper recalls the essentials of 3D transient thermal modeling and shows how the thermal response can be made compatible with a general purpose electrical circuit simulator. The concepts are illustrated by carrying out the electrothermal behaviour simulation of a six -chip power VDMOS transistor module.

   A HYBRID APPROACH TO HEAT TRANSFER MODELING IN ELECTROTHERMAL MODELS OF POWER SEMICONDUCTOR DEVICES
By Z. Lisik [View]
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Abstract: The numerical physical models of power semiconductor devices, based on a solution of the full set of semiconductor equations, are an efficient tool in the CAD technic. Till now a lot of such numerical models, both 1-D and 2-D, have been reported, but only a few of them included thermal phenomena. The introduction of inner feed-back between electrical and thermal phenomena into the models involves some technical problem arising from the fact that in such a model only a small part of the device, limited to the semiconductor chip, is considered, whereas the thermal properties of the device are determined, to a high degree, by its other parts. In the paper a new approach to heat transfer modeling in electrothermal physical models, called a hybrid approach, is presented. It consists in connecting in one thermal submodel both a numerical simulation of heat transfer in the area of semiconductor chip and a non-numerical simulation (based on thermal resistance conception) in the other parts of the device . The presentation is illustrated by some examples of results obtained by means of an electrothermal model of thyristor structure worked out by the author.

EPE 1993 - 27 - Dialogue Session DS1.3: DEVICES: THERMAL EFFECTS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1993 - Conference > EPE 1993 - 27 - Dialogue Session DS1.3: DEVICES: THERMAL EFFECTS
	[return to parent folder]

	DISSIPATION IN POWER SEMICONDUCTOR DEVICES - THE DEVELOPMENT OF THE MAGIC OF i(1+n). Pt. 1 By V. L. Shper	[View] [Download]
Abstract: This work presents the development of Newell's approach to analysis of current capacity of power semiconductor devices. The steady-state average temperature rise for repetitive current waveforms and temperature excursions from a single surge are discussed in detail. New relationships that permit the user to evaluate the current capacity of the devices without knowing the current-voltage characteristics and thermal resistance are derived. For the surge currents the results presented permit the sinusoidal or cosinusoidal pulse to be replaced by equivalent rectangular one for which all necessary calculations can be easily made. The technique of temperature calculation during device cooling after current pulse is defined more precisely than in previous publications and real examples are given.

	TRANSIENT THERMAL EFFECTS DURING TURN OFF IN GTO DEVICES By P. A. Mawby; M. S. Towers; M. Evans; Z. Hu; K. Board	[View] [Download]
Abstract: A rigorous two-dimensional physical model of the GTO thyristor is presented. The model includes the fully coupled effects of self heating of the device during the turn-off phase of operation. The effects of spatially dependent minority carrier lifetime, Auger recombination and carrier-carrier scattering are included in the model. The simulation can be carried out within a realistic external circuit environment.

	A CORRECTION OF MEASURED POWER MOSFET's NORMALIZED TEMPERATURE RESPONSE BECAUSE OF A CASE TEMPERATURE RISE By Z. Jakopovic; Z. Bencic; R. Zunac	[View] [Download]
Abstract: A method of power MOSFET's normalized temperature response (transient thermal impedance) measurement and correction is presented. During semiconductor device's normalized temperature response measurement it is practically impossible to maintain constant case temperature required by a definition of normalized temperature response. Introduced method enables a correction of the measurement error caused by the semiconductor device's case temperature rise. It is based on finding semiconductor device's thermal system model parameters and identifying the point on thermal model which belongs to semiconductor device's case. Measurements of power MOSFET's normalized temperature response are made with a help of a computer controlled electrical method, with semiconductor device mounted on a real heatsink. A developed software package enables: (i) graphical presentation of temperature responses, (ii) identification of semiconductor device thermal system parameters and (iii) correction of measurement error caused by semiconductor device's case temperature rise.

	PARALLELING OF SEMICONDUCTORS INCLUDING TEMPERATURE FEEDBACK, USING SPREADSHEET OR SIMULATION TOOL, TO CALCULATE CURRENT AND TEMPERATURE DIFFERENCES By Terje Rogne; Olve Mo; Manfred Schlürscheid	[View] [Download]
Abstract: Paralleling of semiconductors like IGBTs and diodes is complicated due to the usually negative temperature coefficient of forward voltage drop, and positive temperature coefficient of switching losses. This paper states which component knowledge is necessary as input and then presents two efficient tools for calculating the current and temperature differences of the paralleled semiconductor chips. When using either of the two tools, a spreadsheet or circuit simulation programme, the feedback from the temperature is included through iterations. lt is shown that for instance a 20% imbalance in voltage drop and switching loss may demand a derating down to 32% in a typical chopper application at 20 kHz. With a sinusoidal current, as in a motor inverter, with 20% imbalance, a derating down to 69% is sufficient. Large switching versus conduction losses are very bad when parallelling typical bipolar semiconductors. When parallelling, it is optimal with a faster semiconductor, or a lower frequency, compared to when using one single switch. This paper also gives measured data for various lGBTs, and pictures of measured current sharing between paralleled IGBTs.

	THERMAL MODELING FOR ELECTROTHERMAL SIMULATION OF POWER DEVICES OR CIRCUITS By P. Tounsi; J.-M. Dorkel; Ph. Leturcq	[View] [Download]
Abstract: To perform electro-thermal simulation of power devices or circuits, the authors have developed specific thermal simulation tools which only require limited computational time and effort. 3D and transient flow spreading effects in multilayered substrates commonly used in power component packaging as well as in hybrid power circuits are considered. The paper recalls the essentials of 3D transient thermal modeling and shows how the thermal response can be made compatible with a general purpose electrical circuit simulator. The concepts are illustrated by carrying out the electrothermal behaviour simulation of a six -chip power VDMOS transistor module.

	A HYBRID APPROACH TO HEAT TRANSFER MODELING IN ELECTROTHERMAL MODELS OF POWER SEMICONDUCTOR DEVICES By Z. Lisik	[View] [Download]
Abstract: The numerical physical models of power semiconductor devices, based on a solution of the full set of semiconductor equations, are an efficient tool in the CAD technic. Till now a lot of such numerical models, both 1-D and 2-D, have been reported, but only a few of them included thermal phenomena. The introduction of inner feed-back between electrical and thermal phenomena into the models involves some technical problem arising from the fact that in such a model only a small part of the device, limited to the semiconductor chip, is considered, whereas the thermal properties of the device are determined, to a high degree, by its other parts. In the paper a new approach to heat transfer modeling in electrothermal physical models, called a hybrid approach, is presented. It consists in connecting in one thermal submodel both a numerical simulation of heat transfer in the area of semiconductor chip and a non-numerical simulation (based on thermal resistance conception) in the other parts of the device . The presentation is illustrated by some examples of results obtained by means of an electrothermal model of thyristor structure worked out by the author.