Around the Block(CPF) Versus In the Rows(UPF) Implementation

Now Inorder to implement the mult block defined in the previous session. We have to employ either CPF or UPF. Currently, UPF only support power gating using the "Power Gates in the Rows" approach and CPF only support power gating using "Around the block" approach.

I will first dicuss the flow using the CPF and may be in the Future using the UPF as well.




The picture above is the implementation of this MULT block using CPF(Around the Block) where we have the following three power domains.
1. Power Domain TOP which contains everything except MULT4 and MULT5
2. Power Domain LS(MULT4) which is running at 0.81V only(Upper Right Corner)
3. Power Domain LOW(MULT5) which can Shutdown based on the top level input "pse". (Lower Left Corner)
Notice how MULT4(Power Domain LS) has Separate Power rings around it. This is a separate supply which is less than the Nominal supply of 1.08V in the rest of the block.
Also MULT5(Power Domain LOW) has Power Gates around the block(CPF Implementation).