Questions

To determine which statements about VLSI design are correct, let's analyze each one:

1. Parallelism and pipelining have been effective ways to reduce power consumption.

   • Parallelism and pipelining are techniques used mainly to enhance performance rather than directly reduce power consumption. While they can potentially lead to power efficiency improvements in some scenarios, because of increased energy delays per operation, longer pipeline stages, and increased power due to more active elements, this statement might be too generalized. Therefore, it is mostly considered incorrect in power consumption context.

2. Replacing a single functional unit with an N-stage pipelined unit reduces the amount of logic in a clock cycle at the expense of more registers.

   • This statement is generally correct. Pipeline design involves breaking down a sequential process into multiple stages. Each stage executes part of the operation and passes it on to the next stage. This reduces the logic performed in one clock cycle, though it requires additional registers to hold the intermediate results between stages.

3. When leakage is unimportant, parallelism offers a slight edge because the multiplexer has less overhead than the pipeline registers.

   • This statement is also correct. If leakage current or power is negligible, parallelism has an advantage since the overhead due to extra pipeline registers (needed in pipelining) can be higher compared to the overhead caused by multiplexers (needed for parallelism).

Based on the analysis:

• Statement 1 is mostly incorrect.
• Statements 2 and 3 are correct.

Therefore, the correct answer is: (b) 2 and 3 only