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of the wires.
As a result of the current draws and the nonzero resistance of the wires, the voltage at node k
(which supplies subcircuit k ) has a DC value less than the supply voltage, and also an AC voltage
(which is called power supply ripple or noise). By superposition these two eﬀects can be analyzed
• The DC voltage drop V − vk at node k is equal to the sum of the voltage drops across wires
on the (unique) path from node k to the root. It can be expressed as
vk V− idc
j =1 Ri , (31) i∈N (j,k) where N (j, k ) consists of the indices of the branches upstream from nodes j and k , i.e.,
i ∈ N (j, k ) if and only if Ri is in the path from node j to the root and in the path from node
k to the root.
• The power supply noise at a node can be found as follows. The AC voltage at node k is equal
v k ( t) = − iac (t)
j =1 Ri .
i∈N (j,k) ac
We assume the AC current draws are independent, so the RMS value of vk (t) is given by the
squareroot of the sum of the squares of the RMS value of the ripple...
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This note was uploaded on 09/10/2013 for the course C 231 taught by Professor F.borrelli during the Fall '13 term at Berkeley.
- Fall '13
- The Aeneid