UCC21520: The controller is placed in the secondary side control.

Hi Jimmy,

Thank you for your question. Our expert is out of office today due to the US holiday and will get back to you in the next couple of days. 

Best regards,

Leslie

Hi Jimmy,

The UCC21520 is a dual channel isolated gate driver but the UCC27324 is not. How do you plan on using these two drivers? Do you just need an isolated gate driver? Does the gate driver need to have 2 channels?

We have a comparison table to help explain the differences between our dual channel drivers here: e2e.ti.com/.../faq-what-are-the-differences-between-the-dual-channel-isolated-gate-drivers

Hi Krystian,

Due to the customer putting the controller on the secondary side.Due to Pri and Sec distance too far. They want to isolate the PWM first and use a gate driver to dive the primary side MOSFET.

Like this design as below.The design use ISO7220+UCC27211.I just plan UCC21520 to replace ISO7220

https://www.ti.com/tool/PMP8877?keyMatch=&tisearch=search-everything&usecase=refdesign

Hi Jimmy,

I think the UCC21520 takes care of both functions of ISO7220+UCC27211. The ISO7220 looks like a digital isolator which will isolate the PWM signal and the UCC27211 is a non isolated gate driver. The UCC21520 has isolation and is a dual channel gate driver. You should be able to replace both of those components with the UCC21520. Additionally if you want a dual channel isolated gate driver with single input PWM signals, the UCC20520 is another option.

Regards,

Krystian

Hi Krystian,

Thanks for your explanation. I fully understand the UCC21520 takes care of both functions of ISO7220+UCC27211.

But I want to look at this thing from the point of view of layout. 

I want to put the Gate driver as close to the MOSFET as possible.
But based on safety requirements, I can only put the isolation function on the transformer side.
Then use the Gate driver to drive the MOSFET.

Or  use a totem pole+UCC21520 to replace UCC21520+UCC27324.

So could you give more suggestions? thx