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US 5,857,164 AGranted
System for calculating current consumption characteristics of cells
AssigneeFujitsu Limited
InventorMakoto Wakita
Life of this patent
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Abstract
A system and method for calculating current consumption characteristics of cells of semiconductor circuits is disclosed. According to the invention, the current consumption characteristics of the cells is calculated based on the status changes of the internal memories of the cells. The calculation of current consumption characteristics of cells according to the invention is not only more accurate, but also more efficient in terms of the time needed for logic simulation.
Claims10
A current consumption characteristic calculating system, comprising:
- a static simulation unit that receives schematic information about a cell and executes a static simulation of the cell based on the schematic information to generate a simulation result, the cell having a plurality of input terminals, an internal memory and an output terminal, and the simulation result including signal values of the plurality of input terminals, a status of the internal memory, and a signal value of the output terminal;
- a truth table generator that generates a truth table based on the simulation result;
- an input terminal condition setting unit that sets an operation condition for the cell based on the truth table, the operation condition including signal values of the plurality of input terminals, the status of the internal memory, a signal value of the output terminal and wherein at least one of the signal value of the output terminal and the status of the internal memory changes based on a change in the input signal supplied to a specified input terminal of the plurality of input terminals;
- a measuring circuit adding unit that generates measuring circuit information about a measuring circuit to be added to said cell to measure a consumed current of said cell;
- a transistor reconstructing circuit that reconstructs the cell to include only transistors operating under the operation condition;
- a circuit simulation unit for executing a circuit simulation of the reconstructed cell, based on the operation condition and the measuring circuit information, to provide a summation result of the consumed current of the cell in the operation condition;
- and
- a cell characteristic defining unit that defines a current consumption characteristic of the cell based on the summation result.
5 more elements
A current consumption characteristic calculating method, comprising the steps of:
- receiving schematic information about a cell having a plurality of input terminals, an internal memory, and an output terminal and executing static simulation of the cell based on the schematic information;
- generating a simulation result including respective signal values of the plurality of input terminals, a status of the internal memory, and a signal value of the output terminal;
- generating a truth table based on the simulation result;
- setting an operation condition of the cell based on the truth table, the operation condition including:
- designation of respective signal values of the plurality of input terminals, a status of the internal memory, a signal value of the output terminal, and
- wherein the signal value of the internal memory changes in accordance with a change of an input signal supplied to a specified one of the plurality of input terminals;
- generating measuring circuit information about a measuring circuit to be added to the cell to measure consumed current of the cell;
- reconstructing the cell to include only transistors operating under the operation condition;
- executing a circuit simulation of the cell, based on the operation condition and the measuring circuit information, to provide a summation result for the consumed current of the cell in the operation condition;
- and
- determining a current consumption of the cell based on the summation result.
8 more elements
A computer-readable medium encoded with a program for calculating a current consumption characteristic, said program comprising the functions of:
- receiving schematic information about a cell having a plurality of input terminals, an internal memory, and an output terminal and executing static simulation of the cell in accordance with the schematic information;
- generating a simulation result including respective signal values of the plurality of input terminals, a status of the internal memory, and a signal value of the output terminal;
- generating a truth table based on the simulation result;
- setting an operation condition of the cell based on the truth table, the operation condition including:
- designation of respective signal values of the plurality of input terminals, a status of the internal memory, a signal value of the output terminal, and
- wherein the signal value of the internal memory changes based on a change of an input signal supplied to a specified one of the plurality of input terminals;
- generating measuring circuit information about a measuring circuit to be added to the cell to measure consumed current of the cell;
- reconstructing the cell to include only transistors operating under the operation condition;
- executing a circuit simulation of the cell, based on the operation condition and the measuring circuit information, to provide a summation result for the consumed current of the cell in the operation condition;
- and
- determining a current consumption of the cell based on the summation result .
8 more elements
Dependencies are inferred from the claim text.