UCC28056: UCC28056

Hi Sam,

The UCC28056 can be extended up to 400W, but the UCC28064A is better suited at this power level. Design Calculator is here: https://www.ti.com/lit/zip/sluc645. Product page: https://www.ti.com/product/UCC28064A

Please take at these reference designs as a starting point which are close to your requirements:https://www.ti.com/tool/PMP31179, https://www.ti.com/tool/PMP30763

Regards,

Ray

Hi Sam,

I provided those designs as they're the closest reference designs to your requirements (albeit at 400Hz instead of 60Hz). You will need to adjust values based on the different input frequency range. For the PFC portion, use the calculator with your 400W requirement (and any other changes you need to make). The reference design can be useful for layout and connections with the LLC.

Ray

Hi Sam,

You should use the value provided by the calculator tool (the lesser of the two calculated values). Note that the reference design employs a common inductor, L2 which increases the total boost inductance.

Please consider the reference design as an example and base your design on the particular requirements of your system.

Ray

Hi Sam,

Keep in mind that this is as Transition-Mode (Critical Conduction Mode) PFC, so the frequency will change over the line cycle. RT sets the minimum period timer which dictates the maximum switching frequency. The minimum switching frequency is set by choosing the lower of LH & LL from equations 19 & 20.

Ray

Hi Sam,

It's recommended to design for a switching frequency above the audible range (~25kHz) but below ~65kHz (for EMI purposes), so 50kHz will work. For the final boost inductors value, choose the lower of the two calculated values from equations 19 & 20 (114uH in your case). This will ensure the converter always operates above the desired minimum frequency. When you choose the final standard value, 110uH or 120uH should be close enough.

Regards,

Ray

Hi Sam,

1. That's output ripple (~1.25%)

2. No issue designing for 45kHz to accommodate a more common inductor value.

Ray

Hi Sam,

This question was answered by the PMP30763 designer:

https://e2e.ti.com/support/tools/simulation-hardware-system-design-tools-group/sim-hw-system-design/f/simulation-hardware-system-design-tools-forum/1072021/pmp30763-regarding-external-uvlo-circuit-u13

This thread has the title for UCC28056 and now the discussion has evolved from the UCC28056 to the PMP30763 and UCC28064A. If you have future questions on this, for better support and for the benefit of the wider E2E community, please open a new thread with the PMP30763 and/or UCC28064A product as the subject.

Regards,

Ray