|
|
PDF AN4506 Data sheet ( Hoja de datos )
| Número de pieza | AN4506 | |
| Descripción | Power Assemblies | |
| Fabricantes | Dynex Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de AN4506 (archivo pdf) en la parte inferior de esta página. Total 5 Páginas | ||
|
No Preview Available !
Replaces September 2000 version, AN4506-4.0
AN4506 Application NTGoDte-1X
AN4506
Calculation Of Junction Temperature
Application Note
AN4506-4.1 July 2002
There are a number of ways of calculating the junction
temperature of a device. These involve various levels of
complexity from a quick hand calculation to a full three
dimensional finite element analysis, with various shades
of complexity between these two extremes. Examples of
these various methods are spread sheets and simulation
programs which use some form of mathematical model.
When rating a device for a given application the designer
must select an appropriate type and ensure that absolute
maximum ratings are not exceeded. The device selected
must be rated for the worst case conditions it is likely to
see. If the device rating does not match the circuit require-
ments either a new type must be selected or the circuit
design changed. Alternatively if the device is expected to
fail the circuit must be designed to allow safe failure.
Almost all power semiconductor ratings and characteris-
tics are related to the junction temperature. Consequently
reliable calculation of junction temperature, both transient
and steady state is very important. For simple continuous
current waveforms eg dc, 1/2 sinewave, rectangular waves
etc, used with thyristors rectifiers and GTOs, standard
equations given in textbooks can be used to determine the
junction temperature for a given power loss and thermal
impedance. These are easy to use to calculate Tj. For
irregular shaped current waveforms the pulses can often
be approximated to a series of equivalent energy rectan-
gular pulses. The superposition theorem can then be used
for calculating the junction temperature of a device. This
theorem uses the power losses of a circuit in conjunction
with the transient thermal impedance curve to calculate
the junction temperature of a device.
Junction temperature calculations are extremely depend-
ant on good thermal contacts from chip to heatsink. The
chip to case characteristics are guaranteed by the manu-
facturer, but the case to heatsink characteristics are
dependent upon the way in which the user mounts the
device to the heatsink, surface flatness etc. The final
operating conditions with in a given application, ambient
temperature, heatsink thermal resistance etc all affect the
final T of the device. In any mathematical model used for
j
the calculation of junction temperature, variables such as
these can only be guesstimated from worst case condi-
tions, taking into account reasonable engineering com-
promises regarding heatsink flatness etc. In real life these
values can never be known with 100% accuracy and when
rating a device for a given application maximum toler-
ances should be taken into account. The only way of
evaluating a system fully , is to build it using an approxi-
mately rated device, and test the thermal circuit.
1. POWER LOSSES:
The total power dissipation in a device is the sum of the
switching losses(turn on and turn off), conduction losses,
off state losses and the drive input losses. Only the first 2
of these quantities are generally significant, and at lower
frequencies only the conduction losses are significant.
2. CALCULATION METHODS:
The superposition theorem is based upon rectangular
pulses of power, non rectangular pulses are converted in
rectangular pulses with the same peak power levels, but
with reduced on periods fig 1. The transient thermal
impedance for a given duty cycle can be derived from the
transient thermal impedance single pulse curve fig 2.
P (W)
P1
P2
P (W)
P1
P2
Complex power waveform
t
Modified power pulse waveform
Fig.1
t
www.dynexsemi.com
1/5
1 page  
POWER ASSEMBLY CAPABILITY
The Power Assembly group was set up to provide a support service for those customers requiring more than the basic
semiconductor, and has developed a flexible range of heatsink and clamping systems in line with advances in device voltages
and current capability of our semiconductors.
We offer an extensive range of air and liquid cooled assemblies covering the full range of circuit designs in general use today.
The Assembly group offers high quality engineering support dedicated to designing new units to satisfy the growing needs of
our customers.
Using the latest CAD methods our team of design and applications engineers aim to provide the Power Assembly Complete
Solution (PACs).
HEATSINKS
The Power Assembly group has its own proprietary range of extruded aluminium heatsinks which have been designed to
optimise the performance of Dynex semiconductors. Data with respect to air natural, forced air and liquid cooling (with flow
rates) is available on request.
For further information on device clamps, heatsinks and assemblies, please contact your nearest sales representative or
Customer Services.
http://www.dynexsemi.com
e-mail: [email protected]
HEADQUARTERS OPERATIONS
DYNEX SEMICONDUCTOR LTD
Doddington Road, Lincoln.
Lincolnshire. LN6 3LF. United Kingdom.
Tel: +44-(0)1522-500500
Fax: +44-(0)1522-500550
CUSTOMER SERVICE
Tel: +44 (0)1522 502753 / 502901. Fax: +44 (0)1522 500020
SALES OFFICES
Benelux, Italy & Switzerland: Tel: +33 (0)1 64 66 42 17. Fax: +33 (0)1 64 66 42 19.
France: Tel: +33 (0)2 47 55 75 52. Fax: +33 (0)2 47 55 75 59.
Germany, Northern Europe, Spain & Rest Of World: Tel: +44 (0)1522 502753 / 502901.
Fax: +44 (0)1522 500020
North America: Tel: (613) 723-7035. Fax: (613) 723-1518. Toll Free: 1.888.33.DYNEX (39639) /
Tel: (949) 733-3005. Fax: (949) 733-2986.
These offices are supported by Representatives and Distributors in many countries world-wide.
© Dynex Semiconductor 2002 TECHNICAL DOCUMENTATION – NOT FOR RESALE. PRODUCED IN
UNITED KINGDOM
Datasheet Annotations:
Dynex Semiconductor annotate datasheets in the top right hard corner of the front page, to indicate product status. The annotations are as follows:-
Target Information: This is the most tentative form of information and represents a very preliminary specification. No actual design work on the product has been started.
Preliminary Information: The product is in design and development. The datasheet represents the product as it is understood but details may change.
Advance Information: The product design is complete and final characterisation for volume production is well in hand.
No Annotation: The product parameters are fixed and the product is available to datasheet specification.
This publication is issued to provide information only which (unless agreed by the Company in writing) may not be used, applied or reproduced for any purpose nor form part of any order or contract nor to be regarded
as a representation relating to the products or services concerned. No warranty or guarantee express or implied is made regarding the capability, performance or suitability of any product or service. The Company
reserves the right to alter without prior notice the specification, design or price of any product or service. Information concerning possible methods of use is provided as a guide only and does not constitute any guarantee
that such methods of use will be satisfactory in a specific piece of equipment. It is the user's responsibility to fully determine the performance and suitability of any equipment using such information and to ensure
that any publication or data used is up to date and has not been superseded. These products are not suitable for use in any medical products whose failure to perform may result in significant injury
or death to the user. All products and materials are sold and services provided subject to the Company's conditions of sale, which are available on request.
All brand names and product names used in this publication are trademarks, registered trademarks or trade names of their respective owners.
www.dynexsemi.com
5 Page | ||
| Páginas | Total 5 Páginas | |
| PDF Descargar | [ Datasheet AN4506.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| AN4505 | Power Assemblies | Dynex Semiconductor |
| AN4506 | Power Assemblies | Dynex Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |