Can anybody explain why Carry-Skip adder has the same critical path as regular Carry-Ripple adder. My textbook says that critical path occurs when carry is generated in LSB and then propagating it through the remainder of the adder. The way I see it, critical path occurs when each stage has to either generate or kill carry, therefore every next stage has to wait for the ripple from previous stage to get the sums. All sites are saying that my textbook is correct, but none of them explaining why. I would appreciate any help.
BTW Carry-Skip adder is the same as Carry-Lookahead adder but it doesn't calculate group generate signal.