Hi Shankar ..
Can you please explain power ring ? I know that power mesh is made its width are predefined. But this mesh is made in top metals and is widely discussed in literature.
Hi Shankar
you should calculate the power consume of the chip by the eda tools such as the voltage storm or power meter
Added after 8 minutes:
with the equation P=UI ,so get the I value of the chip
the IR drop max value decide the resistance-- R,
so u can calculate the square resistance . U will get final numbers of strap
a) The width and height of the core area is obtained from estimation sheet
b) Current at the top/bottom and left/right is determined by the following equations
Itop = Ibottom = { Ict * [ Wc / (Wc + Hc)] / 2}
Ileft = Iright = { Ict * [ Hc / (Wc + Hc)] / 2}
Ict = Total core current
Wc = Width of core
Hc= height of core
Depending on the EM limit the total width of the stripe of metal required is
calculated.
Total width of top and bottom = Itop/EM limit
Total width of left and right = Ileft/EM limit
WIDTH DETERMINED BY IR DROP
It is required that the IR drop should be less than 5% VDD
IR drop = I*R
R =R0*(L/2)/W
L/2 is chosen because the drop is maximum here
Hence W= I {*R0*(L/2)}/0.005*VDD
Which ever width is limiting that is taken as the core ring width