UCC28600 120W evaluation module schematic error?

You are correct; the primary side power ground and the primary side signal ground should be connected.  Unfortunately this was cropped in the image for the User Guide.  The layout software that was used at the time would flood the ground plane if the same net name was used for just 'primary side ground" so, in order to force a quiet ground for the signal return that would not have the noise of the power return ground, the two had to be represented as seperate nets...and then jumpered together with a short.  The "short" component somehow gat cut out of the image.  On the layout, JP6 and JP7 are jumpers that will short the signal and power grounds together.

At primary side there are three ground sign, GND1, PWRGND, SIGNAL_GND.

1. Why does it exist GND1 in the PFC circuits?

2. GND1 connects with VOUT_RTN. Does that make sense?

3. Could you provide the gerber of this 120W EVM to me? Previous uploaded gerber is 60W EVM, not 120W EVM.

Thanks

W.H.

the PFC stage is controlled by the UCC28051 and shares a common power ground with the PRIMARY SIDE of the flyback stage which is controlled by the UCC28600.  The SIGNAL_GNDis the quiet ground on the PRIMARY SIDE and this is common to the PRIMARY SIDE PWRGND but laid out in such a way as to keep the high current switching noise away from the small signal paths.  The UCC28600 Flyback stage provides input/output isolation (the PFC stage does NOT provide galvanic isolation, the Flyback stage does).  GND1 is the isolated ground on the SECONDARY side common to the output load.

Yes, the PWRGND and the SIGNAL_GND are on the primary side of the isolation barrier with the PFC stage circuitry.  The GND1 ground is on the secondary side of the isolation barrier and should not be common to either ground on the primary side

Thanks Lisa.

BR

W.H.