Hi,
I am finding a thermal pads or thermal conductive compound for inserting into the interface between the TPS92529Q's thermal pad and heatsink. Would you please give me detail information as following,
1) How much the thermal conductivity of the thermal paste or TIM you are using in TPS92520Q1's 120w 4-channel LED driver boards demo board?
2) Shoud the TIM (thermal interface material) be electrical isolation or electrical isolation is not matter in this design?
B.Regards,
Hello B,
Generally speaking you should try to use electrically isolated thermal interface materials unless you can ensure that all metal touching the thermal interface material and heat sink are at the same potential, which in this case should be ground. The TPS92520's thermal attach pad should be connected to ground.
The heat sink on the EVM uses two different thermal interface materials. Here is diagram of heat sink and the thermal interface materials:
1) Heat sink is 6063 aluminum.
2) The thermal material used to connect the heat sink to the top die attach pad of both the TPS92520s is Chomerics Therm-A-Gap 579 material that is 1 mm thick with a thermal conductivity of 3.0 W/(m-K). Here is the datasheet.
https://www.parker.com/Literature/Chomerics/THERM-A-GAP_500_Series_TB-1016-1-07.pdf
3) The thermal interface material from the heat sink to the bottom of the PCB which is used to cool components on the PCB uses Bergquist SIL-PAD K-10 material which is 0.15 mm thick with a thermal conductivity of 1.3 W/(m-K). Here is the datasheet:
Let me know if you have any other questions.
-fhoude
