UCC28951: Tabset calculation

Henry Wang

Part Number: UCC28951

Tabset etc adapative delay gradually increases as a function of the CS signal, but CS is not a DC voltage, which is changing as primary coil current. What current we need use to calculate the delay time, average current or peak current?

over 1 year ago

0 Mike O' over 1 year ago

TI__Guru* 85916 points

Hello,

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

Regards,

0 Mike O' over 1 year ago in reply to Mike O'

TI__Guru* 85916 points

Hello,

The following link will bring you to an application note that shows how to design the UCC28951 with a fixed delay approach.

This application note shows how to setup all the delay timings for a PSFB design using this approach.

https://www.ti.com/lit/pdf/slua560

Regards,

0 Henry Wang over 1 year ago in reply to Mike O'

Prodigy 20 points

Hi Mike, thanks the feedback. My question is what CS value I need use to calculate the delay, as CS is not a constant DC value. CS is the output of secondary coil of current transformer, which is a triangle waveform.

Best Regards

0 Mike O' over 1 year ago in reply to Henry Wang

TI__Guru* 85916 points

Hello,

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

Regards,

0 Mike O' over 1 year ago in reply to Mike O'

TI__Guru* 85916 points

Hello,

The timing is based on the peak current and not the average. The following link will bring you to an application note that has a section on setting up the current sense transformer and delay timing. You might find this information helpful on setting up the delay timing.

https://www.ti.com/lit/pdf/slua560

Regards,

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UCC28951: Tabset calculation