FPGA Clock Network Power Reduction via Placement Optimization
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Solution Overview
Problem
Modern Field Programmable Gate Arrays (FPGAs) face inefficiencies in clock signal provisioning, leading to excessive leakage and dynamic power consumption due to unoptimized capacitive loads within clock regions, which existing technologies have not adequately addressed.
Innovation Solution
A method for optimal placement of clock signal loads within FPGAs, utilizing a processor-driven system to compare and adjust the placement of load components based on a power reduction cost function, minimizing the number of clock regions and interconnect capacitance, and reducing the usage of vertical clock spines to minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large number of clock signals are provided to each clock region to ensure flexibility and meet various connectivity objectives, then adaptability is improved, but power consumption increases due to excessive capacitive loading
Solution Approach 1:
The patent implements dynamic clock gating control where clock signals are selectively enabled or disabled based on the operational state of logic blocks. The system continuously monitors which logic blocks are actively using clock signals and dynamically adjusts the clock distribution network to provide clocks only to active blocks, thereby reducing capacitive loading and power consumption while maintaining adaptability when needed.
Solution Approach 2:
The patent applies different clock provisioning strategies to different regions of the clock network based on local demands. Instead of uniformly providing clock signals to all clock regions, the system identifies specific regions or logic blocks that require clock signals and provides them selectively, optimizing the balance between adaptability and power consumption for each local area.
2Reliability
If clock signals are provided to all logic blocks to ensure full functionality, then reliability is improved, but power consumption increases due to charging and discharging capacitive loads
Solution Approach 1:
The patent implements periodic monitoring and control of clock signal distribution. The system periodically evaluates which logic blocks require clock signals and adjusts the clock distribution accordingly, enabling full functionality when needed while minimizing power consumption during idle periods through selective clock gating.
Solution Approach 2:
The patent enables logic blocks to effectively request or indicate their clock signal needs, and the clock distribution network responds by providing clocks only to blocks that require them. This self-service mechanism ensures that reliability is maintained for functional blocks while dynamic power consumption is reduced by eliminating unnecessary clock distribution to inactive blocks.
Data Source
AI summary
A method is provided whereby a placement-based cost function is utilized to minimize leakage and dynamic power that is consumed by clock networks implemented within integrated circuits (ICs) such as field programmable gate arrays (FPGAs). An initial placement of clock signal loads is analyzed to determine whether an alternative placement of clock signal loads results in the reduction of the usage of vertical clock spines, or equivalently, the optimization of the cost function. Several desirable characteristics are obtained through strategic clock signal load placement within the FPGA in accordance with the cost function. First, the number of clock regions spanned by a particular clock signal is minimized. Second, interconnect capacitance within the clock region is also minimized. By minimizing the total capacitance of a particular clock network implemented within a clock region, the leakage and dynamic power consumed by the clock network within the clock region is also minimized.