Cadence Design Systems, Inc.

Thomas Andrew Newton

Zhuo Li

William Robert Reece

Charles Jay Alpert

Natarajan Viswanathan

Ruth Patricia Jackson

Amin Farshidi

David Allan White

Mehmet Can Yildiz

Yi-Xiao Ding

Wen-Hao Liu

Jhih-Rong Gao

Derong Liu

Andrew Mark Chapman

Kwangsoo Han

Ainsley Malcolm Pereira

Aspects of the present disclosure address systems, methods, and a user interface for providing interactive skew group visualizations for integrated circuit (IC) design. The method includes causing display of a user interface that includes a display of a grouped view of a clock-tree including a plurality of skew group indicators. The method further includes receiving a user selection of a skew group indicator and updating the user interface to display a detailed view of the skew group including a graphical representation of each clock sink in the skew group and corresponding timing information. The method further includes receiving a second user selection of a first clock sink and in response, the display is updated to display an indicator of a physical location of the first clock sink within the clock tree.

User interface for interactive skew group analysis

Various embodiments provide for clock network generation for a circuit design using an inverting integrated clock gate (ICG). According to some embodiments, a clock network with one or more inverting ICGs is generated, after a topology of the clock network is defined, by applying a non-inverting ICG-to-inverting ICG transform to one or more nodes of the clock network that comprise a non-inverting ICG. Additionally, according to some embodiments, a clock network is generated bottom-up (from the clock sinks to the root clock signal source) using one or more inverting ICGs.

Generate clock network using inverting integrated clock gate

Various embodiments provide for clock network generation for a circuit design using a negative-edge integrated clock gate (ICG). According to some embodiments, a clock network with one or more negative-edge ICGs is generated, after a topology of the clock network is defined, by applying a positive-edge ICG-to-negative-edge ICG transform to one or more nodes of the clock network that comprise a positive-edge ICG. Additionally, according to some embodiments, a clock network is generated bottom-up (from the clock sinks to the root clock signal source) using one or more negative-edge ICGs.

Using negative-edge integrated clock gate in clock network

Electronic design automation systems, methods, and media are presented for cell cloning during circuit design. In one embodiment, for a circuit design comprising a plurality of flip-flop elements having clock inputs provided by a routing tree, a delay is identified for each flip-flop element. The flip-flop elements are clustered by delay to generate at least two clusters of flip-flop elements. Elements within the clusters are then grouped by physical characteristics to generate delay groups of flip-flop elements. An updated routing tree is then generated for the circuit design using the first delay group and the second delay group.

Delay dependence in physically aware cell cloning

Electronic design automation systems, methods, and media are presented for multi-dimension clock gate design in clock tree synthesis. In one embodiment, an input list of clock gate types is accessed, and the list is then used in generating a clock gate matrix. A circuit design with a clock tree is then accessed. The multi-dimensional design involves automatically selecting, for a first clock gate of the routing tree, a first clock gate type from the clock gate matrix based on a size and associated area for the first clock gate type to select a drive strength value for the first clock gate in the routing tree. The first clock gate is then resized to generate a resized first clock gate using the clock gate matrix to adjust a first delay value associated with the first clock gate while maintaining the drive strength value.

Multi-dimension clock gate design in clock tree synthesis

Electronic design automation systems, methods, and media are presented for clock gate placement with data path awareness. One embodiment involves accessing a circuit design with a clock tree, clock gates, and an initial movement area. A set of positions for a set of data path connection points associated with the data routing lines are identified, along with an expansion direction from the initial placement position toward the set of positions for the set of data path connection points, and the initial movement is expanded to consider additional placement options for the clock gate based on the data path connection points.

Clock gate placement with data path awareness

Aspects of the present disclosure address improved systems and methods for generating a clock tree based on route-driven placement of fan-out clock drivers. Consistent with some embodiments, a method may include constructing a spanning tree comprising one or more paths that interconnect a set of clock sinks of a clock net of an integrated circuit device design. The method further includes calculating a center of the set of the clock sinks based on clock sink locations in the integrated circuit device design and identifying a point on the spanning tree nearest to the center of the set of clock sinks. The method further includes generating a clock tree by placing a clock driver at the point on the spanning tree that is nearest to the center of the set of clock sinks.

Route driven placement of fan-out clock drivers

Systems, methods, media, and other such embodiments are described for placement of cells in a multi-level routing tree, where placement of a mid-level parent node between a grandparent node and a set of child nodes is not set. One embodiment involves generating a first routing subregion between a first set of child nodes associated with a first grandparent node and a first connecting route from the first routing subregion to the first grandparent node, which together are set as a first routing region comprising the first routing subregion and the first connecting route. Sampling points are selected along the first routing region, and for each sampling point a set of operating values associated with the sampling point is calculated. A position for the parent node is selected based on the operating values for the sampling points.

Placement of cells in a multi-level routing tree

Aspects of the present disclosure address improved systems and methods for region-aware clustering in integrated circuit (IC) designs. Consistent with some embodiments, the method may include identifying a clustering region for each clock driver included in an IC design based on locations of sinks and blockages, and timing constraints. The CTS tool finds representative locations for each clock driver within their respective clustering regions. Given the representative location for each clock driver, the CTS tool applies point-based clustering to the clock drivers of the IC design to obtain one or more clusters.

Region aware clustering

Various embodiments provide for generation of a clock tree for a circuit design using a mix of a set of buffers and a set of inverters. Some embodiments balance use of buffers and inverters such that the generated clock tree leverages buffers to lower driver count and clock tree, and leverages inverters for lower power usage and duty cycles.

Systems and methods for clock tree generation with buffers and inverters

Aspects of the present disclosure address improved systems and methods for designing an integrated circuit design clock tree structure with scaled-load balanced clusters. Consistent with some embodiments, the system may include a clock tree synthesis (CTS) tool configured to recursively group pins to form a set of clusters that are balanced according to a scaled load. During the recursive grouping, the CTS tool scales actual loads of clusters in accordance with a scaling factor that is based on the radius of the cluster. In this way, the scaling factor penalizes large cluster spans during recursive clustering, thereby producing a clock tree structure that meets design rule constraints.

Balanced scaled-load clustering

Aspects of the present disclosure address improved systems and methods for local cluster refinement during clock tree synthesis for integrated circuit designs. In accordance with some embodiments, the methods for local cluster refinement may include pin move refinement and local reclustering. With pin move refinement, pins are moved from clusters that fail to satisfy design rule constraints to nearby clusters that satisfy design rule constraints. With local reclustering, groups of neighboring clusters that fail or nearly fail to satisfy design rule constraints are dissolved and corresponding pins are regrouped to form new clusters that satisfy design rule constraints.

Local cluster refinement

Systems, methods, media, and other such embodiments described herein relate to generation of routing trees. One embodiment involves accessing a circuit design comprising a source, a plurality of sinks, and a skew threshold associated with the source and the plurality of sinks. An initial routing tree is generated between the source and the plurality of sinks, and then a first intermediate point is identified between the source and the plurality of sinks. The first intermediate point may be identified based on a median location of all sinks of the plurality of sinks, or other criteria. The first intermediate point is then used for an updated routing tree. In some embodiments, a process proceeds iteratively until the skew threshold is reached or a maximum wire length is exceeded.

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Great Cambourne, United Kingdom

Thomas Andrew Newton