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I use the device TL783 in my power supply. The application is current sourcing regulator.
When I put short circuit in the output, the temperature on device, after 10 minutes, rises to 154ºC. The information from datasheet "Operating virtual junction temperature maximum = 150ºC".
Could I use TL783 device in this situation?
Could you explain me how works the safe-operating-area protection with 150ºC on case?
What is the temperature that the thermal shutdown works?
The temperature shutdown occurs around 165C on the TL783. Operation above 125C will greatly reduced the life span of any integrated circuit.What is the input voltage for the TL783, the output current, and required output voltage compliance range?Can the heatsink be improved?
Regards,Ronald MichallickLinear Applications
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Dear Ron Michallik.
Thank for answering.
The circuit in my application is in the file inserted. The current limit is 380 mA, but if occur a short circuit, after 10 minutes, the temperature rises to 154ºC on case. This situation is not common but can be happen. I will change the heatsink to improve my application.
I forgot to do a question:
How many hours the TL 783 can work with 150ºC?
We ran 117 units for a 300 hour life test during qualifcation no no failures occured.More detailed information for MTBF or FITY data is in the Quality & Environmental Data section of the product page.Select view under "DPPM / MTBF / FIT Rate" Download the two excel files and paste the TL783 info into the other spreadsheet.
Here are the results for 150C.
Could you explain me how works the safe-operating-area protection?
I understand that this safe-operating-area change the current limit in function of temperature. Do you have more details or application note about this SOA protection?
Figure 1 in the data sheet (page 4) shows the effect of temperature and voltage differential on maximum output current.
I need a description about this SOA protection.
SOA circuitry protects the TL783 in three ways.1) Over voltage (this protection is only partially effective)2) Over current (prevents metal lines and bond wires)3) Over power (prevents creation of hot spots that cause transistor damage)4) Over temperature (prevent silicon damage from extreme temperature)
We did not find in the datasheet the following specification.
The test is when we put the output of the regulator in short-circuit. When the short-circuit is removed, what is the maximum recovery time for the regulator output coming back to the nominal output voltage?
Please, but we need the answer, with urgency, about the information from the last question to send to our customer.
If the device was in temperature shutdown before removing the short there will be an additional delay as the TL783 cools off a few degrees. This delay will be based on heat sink and airflow which which I am unable to predict. Possibly a couple seconds.
If the device was in current limit before removing the short the TL783 will charge the output capacitor at the current limit level (varies with temperature and Vi-Vo voltage) until the VOUT reaches the nominal level. Time is approximately Cout*Vout(nom)/"Current limit level)
Thank you so much. This explanation was very useful for us.
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