In general, this disclosure is directed to circuitry for implementation of
headswitches and footswitches in an ASIC for power management. The
disclosed circuitry supports not only effective power management, but
also efficient use of ASIC area, reduced complexity, and the use of
electronic design automation (EDA) tools. In this manner, the disclosed
circuitry can support enhanced performance and simplified ASIC design. In
some cases, headswitch or footswitch circuitry may be implemented as a
switch pad ring that extends around a hard macro forming part of an ASIC
core. In other cases, headswitch or footswitch circuitry can be
distributed within an ASIC core by embedding distributed headswitch or
footswitch components under metal layer power routing coupled to standard
cell rows.