International Business Machines Corporation

Amir H Farrahi

Sebastian Theodore Ventrone

David James Hathaway

John Maxwell Cohn

Alvar Antonio Dean

Jagannathan Narasimhan

Scott Alan Tetreault

Thomas M Lepsic

Anthony Richard Bonaccio

Patrick Edward Perry

An electrical wiring structure and a computer system for designing the electrical wiring structure. The electrical wiring structure includes a wire pair. The wire pair includes a first wire and a second wire. The second wire is slated for being tri-stated. The wire pair has a same-direction switching probability &#x3c6;per clock cycle that is no less than a pre-selected minimum same-direction switching probability &#x3c6;or has an opposite-direction switching probability &#x3c6;per clock cycle that is no less than a pre-selected minimum opposite-direction switching probability &#x3c6;. The first wire and the second wire satisfies at least one mathematical relationship involving Land Wwhere Wis defined as a spacing between the first wire and the second wire, and Lis defined as a common run length of the first wire and the second wire.

Wiring optimizations for power

An electrical wiring structure and method of designing thereof. The method identifies at least one wire pair having a first wire and a second wire. The second wire is already tri-stated or can be tri-stated. The wire pair may have a same-direction switching probability per clock cycle that is no less than a predetermined or user-selected minimum same-direction switching probability. Alternatively, the wire pair may have an opposite-direction switching probability per clock cycle that is no less than a predetermined or user-selected minimum opposite-direction switching probability. The first wire and the second wire satisfy at least one mathematical relationship involving: a spacing between the first wire and the second wire; and a common run length of the first wire and the second wire.

A differential sinusoidal signal pair is generated on an integrated circuit (IC). The differential sinusoidal signal pair is distributed to clock receiver circuits, which may be differential amplifiers. The clock receiver circuits receive the differential sinusoidal signal pair and convert the differential sinusoidal pair to local clock signals. Power consumption and noise generation are reduced as compared to conventional clock signal distribution arrangements.

Clock signal distribution utilizing differential sinusoidal signal pair

In integrated circuit (IC) designs, a component of power consumed may be represented as Power&equals;&frac12; FCV , where C is the load capacitance being driven by a source cell, F is the switching frequency of the source cell, and V is the total output voltage swing. However, not every signal value generated by a source cell is required to propagate to all the sink cells connected to the source for every clock cycle of a chip. Accordingly, an isolate cell is inserted in a net (wire) connecting a source cell to at least one sink cell, to de-couple the at least one sink cell and a portion of the net from the source cell when a signal output by the source need not propagate. Due to the de-coupling, the load capacitance associated with the at least one sink and net portion is not experienced by the source cell for such signals. Accordingly, overall IC power consumption is reduced.

Method and apparatus for reducing power consumption in VLSI circuit designs

A method is provided for computing signal and switching probabilities at an output of a logic circuit in a network having multiple logic circuits. The method for computing the signal and switching probabilities includes steps of creating a truth table for a logic circuit where the truth table has entries respectively corresponding to signals at inputs of the logic circuit, choosing in sequence one of entries each representing switching of a signal at the output of the circuit, determining whether a signal at an input corresponding to the chosen entry is at logic high, assigning an event probability representing that the signal is at logic high, and accumulating event probabilities respectively assigned to signals at inputs corresponding to the chosen entries to produce the signal probability at the output of the circuit.

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Amir H Farrahi