*Thank you sir, earlier I knew thermal simulation by only considering thermal resistance. And I always tried to find what should be the value of Thermal capacitance, needed for foster network design. Today it is a bit clear. Thanks sir* 😌😃
Sir, this is very good information.i have one doubt is that the thermal impedence for pulses is actually defining the PWM pulses.so, the same can be used for evaluating the temperature of a Mosfet while it's deployed for MOTOR CONTROLLER Application?
Thank you for the video sir! I had one question about the thermal impedance curves. In all the graphs the pulse duration seems to be the only important variable for determining the thermal impedance, however the thermal conductivity of the material (lets say silicon) also changes with temperature. So should the thermal impedance not also be dependent on the temperature of the material? or is it negligible
Use a pair of relays. On each unit, wire it so that the thermostat signal goes through the NC contacts of the other unit. Then wire the coils so that it activates when its corresponding unit turns on. So turn on one and the relay disconnects the signal for the other one. Turn on the other one and nothing happens until the first one turns off.
I have one question the provided value of Rthja in the datasheet ..does that represent worst case value? If it represents worst case value then is it only under the JEDEC recommended pad area and testing environment..it may be more or may be less as per the user pcb boards. Is my understanding correct?
Mr. Sam, speaking of hestsinks and thermal resistances, how would we do in a situation where we want to use the PCB copper as heatsink for SMD devices. How can we calculate the thermal resistance or copper area in order to get certain temperature on the SMD device ?
You need to do thermal simulation but most vendor s give the thermal hesitance of SMD when already on copper of certain area and some are giving for several different areas.
Sam Ben-Yaakov Then, knowing the resistance for a given area, we can compute the new resistance for a new area knowing that the resistance is inversely proportional to the area, is this a way to go to avoid thermal simulation ?
/ @@nachiketadeshmukh8444 K is basically one but if large temperature drops are expected within the mass one can account for them by adjusting K. It can be estimated experimentally measuring the temp rise of a short thermal pulse so that the loss due to thermal conduction is still small
@4:01 so after 0.1 second where curve is flat ( equilibrium) do we need to consider capacitor in the model if anyone want to analyse for longer pulse let's say 2 sec
Thank you prof. Ben-Yaakov. This was exactly what I was searching for to estimate junction temperature of IGBT for single pulse application.
Glad it was helpful!
*Thank you sir, earlier I knew thermal simulation by only considering thermal resistance. And I always tried to find what should be the value of Thermal capacitance, needed for foster network design. Today it is a bit clear. Thanks sir* 😌😃
Thanks for comment.
Great explanation! Many Thanks!
Thanks
Very good presentation as usual, Sam !
👍😊
Well done, great job as always!
Thanks. Welcome to join www.linkedin.com/groups/13606756
As always , BEST^n.
Thanks😊
Sir, this is very good information.i have one doubt is that the thermal impedence for pulses is actually defining the PWM pulses.so, the same can be used for evaluating the temperature of a Mosfet while it's deployed for MOTOR CONTROLLER Application?
Thanks for comment. Yes indeed. At low modulation frequency typical of motor drive this could be significant.
Thank you for the video sir! I had one question about the thermal impedance curves. In all the graphs the pulse duration seems to be the only important variable for determining the thermal impedance, however the thermal conductivity of the material (lets say silicon) also changes with temperature. So should the thermal impedance not also be dependent on the temperature of the material? or is it negligible
Good point. I don't know what is the temp effect on the thermal resistance. I would guess that it is minor.
Hi! Nice video, but how do you calculate Rth1,2,3,4, Cth1,2,3,4?
Which miniate in the video are you referring to?
@@sambenyaakov at 7:00 when there are 5 RC blocks? How can I calculate the R C parameters?
Now translate to the temperature of the transistor junction.
Tj=Tcase+Ploss*Zjc
cool i have 2 ac units i need too find away so to cant run at the same time like if some turn on one 2 cant run it cut the power off on one
Use a pair of relays. On each unit, wire it so that the thermostat signal goes through the NC contacts of the other unit. Then wire the coils so that it activates when its corresponding unit turns on. So turn on one and the relay disconnects the signal for the other one. Turn on the other one and nothing happens until the first one turns off.
Thanks.
Is it digital or analog?
?
@@sambenyaakov Can we say that this circuit is digital or analog? The thermal modelling.
I am working on a project called "Thermal Macromodelling of digital electronics systems". Does this include in digital electronics systems.
@@msudaiskhan This applies to any sstem in pulse operation
I have one question the provided value of Rthja in the datasheet ..does that represent worst case value? If it represents worst case value then is it only under the JEDEC recommended pad area and testing environment..it may be more or may be less as per the user pcb boards.
Is my understanding correct?
Look for the commnets and samll prints in data sheet for specification of copper area for which the Rth is quoted.
Mr. Sam, speaking of hestsinks and thermal resistances, how would we do in a situation where we want to use the PCB copper as heatsink for SMD devices. How can we calculate the thermal resistance or copper area in order to get certain temperature on the SMD device ?
You need to do thermal simulation but most vendor s give the thermal hesitance of SMD when already on copper of certain area and some are giving for several different areas.
Sam Ben-Yaakov Then, knowing the resistance for a given area, we can compute the new resistance for a new area knowing that the resistance is inversely proportional to the area, is this a way to go to avoid thermal simulation ?
What is "K" in the last slide?
A scaling constant
@@sambenyaakov Thank you for your reply. How can we determine its value?
/ @@nachiketadeshmukh8444 K is basically one but if large temperature drops are expected within the mass one can account for them by adjusting K. It can be estimated experimentally measuring the temp rise of a short thermal pulse so that the loss due to thermal conduction is still small
@4:01 so after 0.1 second where curve is flat ( equilibrium) do we need to consider capacitor in the model if anyone want to analyse for longer pulse let's say 2 sec
Indeed