UCC2897A: Some questions about the SLUA702

Bell Ye

Intellectual 1135 points

Part Number: UCC2897A

Hi,

I may have some small questions about the SLUA702, could you pls read below and try to help?

On page2, Hvi(s) is used but in figure 2, it’s Hdi(s) in block. I’m afraid I’m puzzled. Any typing error here?

In figure 2, Ri is used, but in Figure 3, Rs is used.

What’s definition of Rs, Ri? I guess it’s something like Rs=gain* Ri, where Ri is sense resistor. Is that correct? How much gain shall I use here for UCC2897A?

thanks,

Bell

over 8 years ago

0 Peter Meaney over 8 years ago

TI__Mastermind 31580 points

Hi Ye,

I have asked one of our applications engineers to respond to your question. You should see an answer later today.

Regards

Peter

0 Benjamin Lough over 8 years ago in reply to Peter Meaney

TI__Mastermind 27105 points

Hi Bell,

Ri and Rs both refer to the sense element (the current sense resistor). You can size the sense resistor based on the expected primary current and the current sense threshold of UCC2897A.

I was not able to confirm Hvi(s) and Hdi(s) are the same. I have emailed the author of the application note and will get back to you. I have also emailed you some supplemental material concerning small signal modeling of active clamp forward.

Best Regards,
Ben Lough

0 Bell Ye over 8 years ago in reply to Benjamin Lough

TI__Intellectual 1135 points

Hi Ben,

Thanks for your help. Do you get some updates on the confirmation of Hvi(s) and Hdi(s)?

thanks,
Bell

0 Benjamin Lough over 8 years ago in reply to Bell Ye

TI__Mastermind 27105 points

Hi Bell,

I haven't received a response from him yet. I'll ping him again.

Best Regards,

Ben Lough

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UCC2897A: Some questions about the SLUA702