US 7,030,658 B2 · Systems and methods for operating logic circuits

Abstract

Systems and methods for reducing the power consumption of some combinations of logic gates by reducing the number of unnecessary transitions that are made by logic gates that do not affect the output of the logic. In one embodiment, a modified exclusive-OR (XOR) gate is coupled to a modified multiplexer. The XOR gate has two inputs, Ain and Bin, and an output, XORout, which is provided as an input to the multiplexer. Another input to the multiplexer is Cin. A select signal is input to the multiplexer to select either Cin or XORout to be provided at the output of the multiplexer. If XORout is selected, the XOR gate operates in a first mode in which it functions as a normal XOR gate. If Cin is selected, the XOR gate operates in a second mode in which the XOR gate uses less power than when the XOR gate operates normally.

Claims18

Dependent claims

A system comprising:

a first logic circuit configured to receive one or more logic circuit input signals and to generate a logic circuit output signal;
and
a multiplexer configured to receive the logic circuit output signal and one or more additional signals as multiplexer input signals, wherein the multiplexer is configured to receive a select signal that controls the multiplexer to select one of the multiplexer input signals to be provided as a multiplexer output signal;
wherein when the select signal controls the multiplexer to select the logic circuit output signal as the multiplexer output signal, the first circuit operates in a first mode, and when the select signal controls the multiplexer to deselect the logic circuit output signal as the multiplexer output signal, the first circuit operates in a second mode wherein the second mode comprises a power-saving mode.

1 more element

Dependencies are inferred from the claim text.

Systems and methods for operating logic circuits

Life of this patent

Systems and methods for operating logic circuits

Life of this patent

Abstract

Claims18