UCC21521: PSFB converter design using UCC21521 + UCC28950

Hi Umang,

Thank you for your interest in our products!

It looks like the UCC27714EVM is using the digital isolator as an isolation for the control signal. Our isolated gate drivers will have the isolation between the control side and the power side built in internally.

Umang Butani said:

Also, Some non-reel parts of UCC21521 are NRND, Will UCC21521 be obsolete in near future?

Correct, the newer generation of this device is UCC21551.

Here is the link to the product page: https://www.ti.com/product/UCC21551 

The UCC21551 EVM is found here: https://www.ti.com/tool/UCC21551CQEVM-079 

For reference designs, you can refer to UCC21520 reference designs found here: https://www.ti.com/product/UCC21520#reference-designs 

UCC21551 is mostly p2p with UCC21520 so these reference designs will be helpful to refer to when designing your application.

Please feel free to ask any additional questions below if needed.

Regards,

Hiroki

Dear Hiroki, 
Yes, Based on datasheet of UCC21551, Primary side VCCI max can go upto only 6V, because of this INA and INB will be limited to maximum of 6VDC only, where output signal of UCC28950 OUTA to OUTE will have 12VDC range, this will create electrical issue in design. 
Because of these UCC21521 was the prefered choice, Do you have any newer generation device where its primary voltage can go upto 12VDC. 
If you have any other solutions in mind, Please do share. 

Best regards, 
Umang 

Thanks Hiroki, 
Yes, This Its seem to be an ideal choice, though we have one doubt, 

Our secondary side voltage is approx 12VDC, for FET driver, will this IC work fine with it? 
As I Was going through datasheets, It looks like it require voltage more than 14.7V as per below table! 

 

JFY, We will use bootstrape power supply mode. 

Can you please help us to understand it better?  Do we have to increase our VDDA and VDDB above 14.7?  

Thanks and Regards, 
Umang

Hi Umang,

Thanks for reaching out.

We're currently closed today in observance of Labor Day. We'll get back to you once we're back in office.

Best,

Pratik