I'm building a small battery powered device which contains an ATTiny85 micro controller, a dual common anode 7 segment display and 2x595 shift registers to drive the 7 segment display.
The device will spend most of its time sleeping. While in sleep mode, the 7 segment display will be off. The 595s have a worst case quiescent current of 160uA so with both of them on its a full 320uA of wasted current.
What would be the most efficient method of turning off the 595s when they are not used?