Patent ID: 7454738

Claim:
A method to control the amount of power used by a combinational logic circuit implementing a logic function, the method comprising the steps of: converting the logic function to a sum of at least two sub-functions, to determine an idle portion of the logic circuit and to determine an active portion of the logic circuit according to the Shannon expansion method, wherein one of the at least two sub-functions includes a first control variable and a first cofactor and the other of the at least two sub-functions includes a second control variable and a second cofactor; providing a logic circuit including the idle portion and the active portion and a first cofactor circuit based on the first cofactor and a second cofactor circuit based on the second cofactor; providing a first control gate coupled to the first cofactor circuit and a second control gate coupled to the second cofactor circuit; disconnecting the power from the idle portion of the circuit; and connecting the power to the active portion of the circuit while the power is disconnected from the idle portion of the circuit.