Using LNKSwitch TN2 to supply 12V to for HiperLCS and HiperPFS-3

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I am planning on using the LNKSwitch as shown in the RDR506 reference design to supply 12V for the HiperPFS-3 and HiperLCS as shown in the DER394 and RDR239 reference designs.

My concern is the grounding and EMI filtering.
The ground of the 12V for the RDR506 is connected only through a diode to the the AC input.
It looks as if in the DER394 reference design they specificially seperate the 12V ground from the input AC and the 385V DC output.
I am concerned about connecting the grounds between the DER394 and RDR-239 as the RDR-239 has a split ground plane as well.

Hi rf,

Connect L(TP1) of RDR-506 to +C7 of DER-394.
Remove/short D2 of RDR-506 then connect N(TP2) to -C7 of DER-394.
Connect output of RDR-506 to VCC supply of DER-394 and VCC of RDR-239.
You can already remove the Vcc supply pre-regulator of DER-394 since the output of RDR-506 is regulated enough.
Then just connect output(Bulk cap) of DER-394 to input of RDR-239.

Their grounds are internally connected on the IC of DER-394 and RDR-239 so it is ok to connect the ground together.

You might need to increase slightly the regulation of RDR-506 to 12.5-13V so that you have more margin on PFS and LCS UVLO.

Thanks, this really helps. I am also considering using an LR745 as a VCC generator for the hiperpfs. It only can supply two amps so it does not look like it can supply the hiperlcs. Any hints in using the LR745?

**The LR745 only supplies 2mA
Powering the PFC with the LR745 still leaves the HiperLCS to be powered. How would I use the TN2 to power only that portion?