Method and apparatus for reducing optical emissions in an integrated circuit

摘要

A method of hindering optical detection of a pattern of data being stored, moved or processed by at least one active circuit in an integrated circuit, the active circuit including at least first and second active devices that change state within a period of time, such that each device exhibits low resistance in one state and high resistance in another state, the method comprising controlling timing of the change of state of the first active device relative to the second active device so as to prevent the devices having simultaneous intermediate resistances between the low and high resistances, thereby to reduce optical emission by the at least one active circuit compared to causing the changes of state of the two devices to happen simultaneously.