A method for selectively coupling portions of memory to different voltage rails, the method comprising: determining a current active mode of a subsystem of a computing device comprising a memory; determining a current operating mode of each of a plurality of memory portions of the memory that are individually power collapsible and comprised in the subsystem; controlling each of a plurality switching circuits based on the current active mode of the subsystem, and the current operating mode of each of the plurality of memory portions, each switching circuit configured to selectively couple a corresponding one of the plurality of memory portions with a first voltage rail or a second voltage rail; sending a trigger signal for switching the plurality of switching circuits to each of a plurality of memory array sequencers when the subsystem changes from a first active mode to a second active mode, the plurality of memory array sequencers corresponding to the plurality of switching circuits and plurality of memory portions; setting a state of each of the memory array sequencers based on the current operating mode of the corresponding memory portion; selectively passing the trigger signal to its corresponding switching circuit based on the state of the memory array sequencer; and causing each of a plurality of multiplexers corresponding to the plurality of memory array sequencers to pass to another one of the plurality of memory array sequencers either the trigger signal as received from the corresponding switching circuit of the corresponding memory array sequencer or the trigger signal as received bypassing the corresponding memory array sequencer based on the state of the corresponding memory array sequencer. determining a current active mode of a subsystem of a computing device comprising a memory; determining a current operating mode of each of a plurality of memory portions of the memory that are individually power collapsible and comprised in the subsystem; controlling each of a plurality switching circuits based on the current active mode of the subsystem, and the current operating mode of each of the plurality of memory portions, each switching circuit configured to selectively couple a corresponding one of the plurality of memory portions with a first voltage rail or a second voltage rail; sending a trigger signal for switching the plurality of switching circuits to each of a plurality of memory array sequencers when the subsystem changes from a first active mode to a second active mode, the plurality of memory array sequencers corresponding to the plurality of switching circuits and plurality of memory portions; setting a state of each of the memory array sequencers based on the current operating mode of the corresponding memory portion; selectively passing the trigger signal to its corresponding switching circuit based on the state of the memory array sequencer; and causing each of a plurality of multiplexers corresponding to the plurality of memory array sequencers to pass to another one of the plurality of memory array sequencers either the trigger signal as received from the corresponding switching circuit of the corresponding memory array sequencer or the trigger signal as received bypassing the corresponding memory array sequencer based on the state of the corresponding memory array sequencer. <EOS>