Other Parts Discussed in Thread: ISO5852S
Hi team,
Is it possible to connect multiple transistors in the circuit shown in Figure 45 of the UCC21750 datasheet?
All transistors turn on at the same time.
Sincerely.
Ryu
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Ryu,
Yes this is possible, and not uncommon.
each IGBT should have its own seperate external gate resistors placed close to each IGBT pins.
As Collectors/emitters are shorted, there only needs to be one desat HV diode going to the shared collector node.
I would actually point you to look at this reference design we have for ISO5852S driving parllel IGBTs. The main difference is that this reference design has a current buffer which you presumably aren't going to use, other than that, the design is a good starting point/reference for this
https://www.ti.com/tool/TIDA-00917
If this answers all your questions, please let me know by pressing the green Resolved button.
Best
Dimitri
Hi Dimitri,
Thanks for your reply.
My question was whether one IC can be connected to more than one transistor.
That is how it is used in Figure 45.
The method you gave me is to operate multiple ICs in parallel?
Sincerely.
Ryu
Ryu-san,
The reference design shows driving multiple transistors with just one IC, just shared it as a starting point to share with customer.
This is also shown in Figure 61 of the datasheet.
If this answers all your questions, please let me know by pressing the green Resolved button.
Best
Dimitri
Hi Dimitri,
Thanks for your reply.
My apologies for my lack of explanation.
I want to connect a mirror clamp circuit with multiple transistors as shown in Figure 45.
That is, can I connect the CLMPI pin to the base of multiple transistors?
Sincerely.
Ryu
Ryu-san,
I want to connect a mirror clamp circuit with multiple transistors as shown in Figure 45.
That is, can I connect the CLMPI pin to the base of multiple transistors?
You can definitely do this this.
Depending on the number, size of the transistors, and physical placement on the board, some customers switch to UCC217xx with CLMPE pin to control an external mosfet for miller clamp.
I would say if the placement of your parallel FETs are relatively close, and you will not use a buffer, that you dont need external miller clamp FET, there isn't really a need to do this.
This is most helpful when the driver is really far away from the transistor.
Best
Dimitri
Ryu-san,
I'm glad to hear that!
Just for your reference, we have a comparison table for UCC217xx family of drivers in E2E located at link below,
Might be useful in the future.
Please dont hesitate to reach out if you have any more questions.
Best
Dimitri