AC/AC Line Switch Solid State Circuit Breaker

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Charlie010
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First reply posted First question asked Welcome!

we are focus on solid circuit breaker topic. and  i am interesting in the Si/SiC product from infineon. now i want to know some optimize design for thermal case of IPQC60R010S7

from the datasheet, i get the thermal resistance ,junction-ambient for SMD version RthJA=45℃/W.  I think this value is also

can not be accepted in our application. As I calculation, we will use in 60A/230VAC system. that means when MOSFET is on, the current flow will be 60A,  and the Rdson=0.01Ω, we still have P =60*60*0.01=36W. and the temperature-rise will be 

T=36*45=1620K, it's so hot for our industrial applications (85℃).

I want to know do you have some solution for our application to solve the thermal case? thanks in advanced.

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1 Solution
Neo_Qin
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Hi @Charlie010 ,

RthJA=45℃/W  is obtained under specific test conditions, as you can see below.

Neo_Qin_0-1676873146740.png

The highlight of IPQC60R010S7 is the QDPAK package which come in top-side cooled (TSC) , has an exposed pad to dissipate the generated heat. The actual RthJA value depends on your thermal design, typically much smaller than the values listed in the table.

Another important parameter, Rds(on)=10mohm, is measured at Tj=25℃,this is impossible in real scenarios.

Considering the derating of Tj (125℃ in this case), 19.8mohm @Id=50A may be a more accurate value.

Increasing the Vgs voltage can also reduce Rds(on), as you can see in the figure 7.

Neo_Qin_1-1676875407249.png

In your application, a single IPQC60R010S7 may not be able to withstand a continuous current of 60A, you need to consider 2~3 devices in parallel. Obviously this is an AC application, so you have to connect 2 MOS in series to get the blocking capability. Eventually, you may need 4~6 devices in a 60A channel.
More details about TSC, please refer to the following Infineon AN:

Innovative top-side cooled package solution for high-voltage applications 

Regards,

Neo

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3 Replies
Neo_Qin
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5 likes given 250 replies posted 250 sign-ins

 

Hi @Charlie010 ,

RthJA=45℃/W  is obtained under specific test conditions, as you can see below.

Neo_Qin_0-1676873146740.png

The highlight of IPQC60R010S7 is the QDPAK package which come in top-side cooled (TSC) , has an exposed pad to dissipate the generated heat. The actual RthJA value depends on your thermal design, typically much smaller than the values listed in the table.

Another important parameter, Rds(on)=10mohm, is measured at Tj=25℃,this is impossible in real scenarios.

Considering the derating of Tj (125℃ in this case), 19.8mohm @Id=50A may be a more accurate value.

Increasing the Vgs voltage can also reduce Rds(on), as you can see in the figure 7.

Neo_Qin_1-1676875407249.png

In your application, a single IPQC60R010S7 may not be able to withstand a continuous current of 60A, you need to consider 2~3 devices in parallel. Obviously this is an AC application, so you have to connect 2 MOS in series to get the blocking capability. Eventually, you may need 4~6 devices in a 60A channel.
More details about TSC, please refer to the following Infineon AN:

Innovative top-side cooled package solution for high-voltage applications 

Regards,

Neo

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Hello Neo,

Thanks for your support. I have one more question. I see there are an aluminum heat sink in the document.

do you offer the aluminum heat sink for us? or do you sale the  module combine two MOSFET and aluminum?  

Charlie010_0-1676880183776.png

 

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Neo_Qin
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Hi @Charlie010 ,

First of all, sorry for the error in my previous reply. I mistaken IPQC60R010S7 (BSC: bottom side cooling) for IPDQ60R010S7 (TSC: top side cooling). Fortunately, the conclusion is correct because the electrical parameters are the same.

Since the test board mentioned in AN_Chapter_4  is not an evaluation board/reference design, the coldplate, or  aluminum heat sink is not available for the end-customers.

It's recommended that you refer to the KIT_ACT_BRD_S7_4PIN  to make a simple test board for temperature rise evaluation. And special structuring of the coldplate is not necessary, you can totally use the shelf products on the market as an alternative.

When comparing the performance of the TSC vs. BSC on FR4 PCB, the thermal performance of the TSC is improved,  potential gains as a result of PCB area reduction and EMC noise mitigation can be expected. IPDQ60R010S7 maybe a better choice in your application.

Dealing with 60A current level is not easy, Good luck.

If you have any concerns, kindly let me know.

BR,

Neo

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