UCC28951: Primary current control of PSFB converter using UCC28951

Abhinav Soni

Part Number: UCC28951
Other Parts Discussed in Thread: LM5046

Hey All,

I'm working on a PSFB converter and wanted to control just the primary RMS current of the transformer, I was wondering if the UCC28951/LM5046 can work with just such an application. I'm not sensing the input current, but the AC current through the leakage inductance (I don't need to regulate the output voltage), Would the IC still work in this way too? Or do I need to employ other feedback mechanisms as well?

Best Regards

Abhinav

over 2 years ago

0 Mike O' over 2 years ago

TI__Guru* 86286 points

Hello,

I am reviewing your inquiry and will get back to you shortly.

Regards,

0 Mike O' over 2 years ago in reply to Mike O'

TI__Guru* 86286 points

Hello,

I believe that customers have done CC/CV design with both devices. If that is what you are looking to do that is possible.

Regards,

0 Abhinav Soni over 2 years ago in reply to Mike O'

Prodigy 50 points

Hey,
What I mean is, if I don't give any voltage feedback to the controller, and just give a sensed current (leakage inductor current which is rectified and converter to voltage through a buffer resistor), would the controller still work in that case? As I don't intend to do secondary side regulation for my application.

0 Mike O' over 2 years ago in reply to Abhinav Soni

TI__Guru* 86286 points

Hello,

I am reviewing your inquiry and will get back to you shortly.

Regards,

0 Mike O' over 2 years ago in reply to Mike O'

TI__Guru* 86286 points

Hello,

If you want to develop your own control scheme. You could set the voltage amplifier up in a follower EA - connect to comp out. You would then control the magnitude of the current at the CS pin with voltage applied to the EA + pin.

Regards,

0 Abhinav Soni over 2 years ago in reply to Mike O'

Prodigy 50 points

Hey Mike,
Do you mean that I connect an external Op-Amp circuit (voltage follower) with the current feedback that I am getting, and connect it to the COMP pin? For the CS pin, I connect just the current sense feedback ?

Regards
Abhinav

+1 Mike O' over 2 years ago in reply to Abhinav Soni

TI__Guru* 86286 points

Hello,

If you just want to control the current you can do this or you can use a CC/CV feedback scheme.

Regards,

0 Abhinav Soni over 2 years ago in reply to Mike O'

Prodigy 50 points

Hey Mike,
I think that would work with the controller, I also checked the internal blocks, and it should work that way!

Thanks!

0 Mike O' over 2 years ago in reply to Abhinav Soni

TI__Guru* 86286 points

Hello,

Thanks for the feedback.

Regards,

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UCC28951: Primary current control of PSFB converter using UCC28951