In one embodiment, a method for power mode transition in a multi-threshold
complementary metal oxide semiconductor (MTCMOS) circuit includes
clustering logic cells in the circuit to a number of logic clusters and
optimizing wake-up times of the logic clusters to reduce a total turn-on
time of the circuit while keeping below a predetermined threshold a sum
of currents flowing from the circuit to ground, a sum of currents flowing
from a supply voltage to the circuit, or both during a transition by the
circuit from sleep mode to active mode.