摘要:
In a method of estimating a leakage current in a semiconductor device, a chip including a plurality of cells is divided into segments by a grid model. Spatial correlation is determined as spatial correlation between process parameters concerned with the leakage currents in each of the cells. A virtual cell leakage characteristic function of a cell is generated by arithmetically operating actual leakage characteristic functions. A segment leakage characteristic function of a segment is generated by arithmetically operating the virtual cell leakage characteristic functions of all cells in the segment. Then, a full chip leakage characteristic function of the chip is generated by statistically operating the segment leakage characteristic functions of all segments in the chip. Accordingly, computational loads of Wilkinson's method for generating the full chip leakage characteristic function can remarkably be reduced.
摘要:
In a method of estimating a leakage current in semiconductor device, a chip including a plurality of cells is divided into segments by a grid model. Spatial correlation is determined as spatial correlation between process parameters concerned with the leakage currents in each of the cells. A virtual cell leakage characteristic function of the cell is generated by arithmetically operating actual leakage characteristic functions. A segment leakage characteristic function is generated by arithmetically operating the virtual cell leakage characteristic functions of each cell in the segment. Then, a full chip leakage characteristic function is generated by statistically operating the segment leakage characteristic functions of each segment in the chip. Accordingly, the computational loads of Wilkinson's method for generating the full chip leakage characteristic function may be remarkably reduced.
摘要:
Provided is a method of incremental SSTA (statistical static timing analysis) of a digital circuit, the method including a first step in which, when a gate is replaced in the digital circuit, delay propagation is performed from a node of a replaced gate to a virtual sink node based on SSTA; a second step in which, if a changed value of a gate timing yield at each gate which propagates delay toward the virtual sink node is smaller than a predetermined threshold value, delay propagation with respect to a fanout gate of the corresponding gate is stopped; and a third step in which, when a delay with respect to the node of the replaced gate is propagated to the virtual sink node, a new timing yield is calculated at the virtual sink node.
摘要:
Provided is a method of optimizing statistical timing of an integration circuit, the method including applying subtle changes of mean arrival times with respect to each of nodes in a timing graph of an integrated circuit to ADD operations and MAX operations of a block-based statistical static timing analysis (SSTA) method and approximating the corresponding operations; generating Jacobian matrixes between each node by using matrix components including differential coefficients calculated during linear approximation of the operations; calculating changed arrival time values of the circuit by propagating the Jacobian matrixes from a virtual sink node to a virtual source node; and calculating timing yield criticalities, which are variances of timing yield of the circuit due to subtle changes of mean arrival times with respect to each node, based on values obtained by the propagation. Accordingly, timing yield criticality is calculated based on linear approximation of ADD operations and MAX operations of statistical static timing analysis (SSTA), and thus the calculation complexity is linear with respect to the total number of nodes, and critical nodes significantly affecting the timing yield of a circuit can be extracted more accurately.
摘要:
Provided is a method of optimizing statistical timing of an integration circuit, the method including applying subtle changes of mean arrival times with respect to each of nodes in a timing graph of an integrated circuit to ADD operations and MAX operations of a block-based statistical static timing analysis (SSTA) method and approximating the corresponding operations; generating Jacobian matrixes between each node by using matrix components including differential coefficients calculated during linear approximation of the operations; calculating changed arrival time values of the circuit by propagating the Jacobian matrixes from a virtual sink node to a virtual source node; and calculating timing yield criticalities, which are variances of timing yield of the circuit due to subtle changes of mean arrival times with respect to each node, based on values obtained by the propagation. Accordingly, timing yield criticality is calculated based on linear approximation of ADD operations and MAX operations of statistical static timing analysis (SSTA), and thus the calculation complexity is linear with respect to the total number of nodes, and critical nodes significantly affecting the timing yield of a circuit can be extracted more accurately.
摘要:
Provided is a method of incremental SSTA (statistical static timing analysis) of a digital circuit, the method including a first step in which, when a gate is replaced in the digital circuit, delay propagation is performed from a node of a replaced gate to a virtual sink node based on SSTA; a second step in which, if a changed value of a gate timing yield at each gate which propagates delay toward the virtual sink node is smaller than a predetermined threshold value, delay propagation with respect to a fanout gate of the corresponding gate is stopped; and a third step in which, when a delay with respect to the node of the replaced gate is propagated to the virtual sink node, a new timing yield is calculated at the virtual sink node.
摘要:
A display device, and a blower thereof are disclosed. The display device includes an axial flow fan within a case, which has a display panel encased therein. The axial flow fan is provided in a width direction within the case, so that, while being rotated within the case, the axial flow fan generates forced air flow suitable to the case. The forced air flow is generated in a forward direction along with air flow by natural convection within the case.
摘要:
Disclosed herein are an adhesive sheet comprising a cured acrylic polymer, hollow polymeric microspheres dispersed and ruptured in the cured acrylic polymer, and hollow parts formed by rupturing the hollow polymeric microspheres dispersed in the cured acrylic polymer, and a preparation method thereof.
摘要:
Disclosed is a cooling fan including a fan rotated by a motor, for forcibly circulating the air, and a fan housing having a through hole with a predetermined inside diameter so that the fan can be mounted thereon. A curvature radius of the end of the inner circumference of the through hole sucking the air is smaller than a curvature radius of the end of the inner circumference of the through hole discharging the air. As a result, the cooling fan can minimize noises in the operation.
摘要:
A semiconductor optical device and a method for fabricating the same. The semiconductor optical device comprises a substrate, a semiconductor electrode layer of a first conductive type formed on the substrate and having a groove formed to a desired depth therein, a semiconductor layer of the first conductive type formed from side walls of the groove up to a part of the semiconductor electrode layer of the first conductive type on the periphery of the groove, a cladding layer of the first conductive type, an active layer of the first conductive type, a cladding layer of a second conductive type and a semiconductor electrode layer of the second conductive type sequentially formed on the semiconductor layer of the first conductive type, and electrodes of the first and second conductive types formed respectively on the semiconductor electrode layers of the first and second conductive types.