Stripe-Based Self-Gating for Retiming Pipeline Power Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In large retiming pipelines, clock gating techniques increase power consumption without a corresponding area increase, and existing methods for reducing power consumption in self-gating circuits lead to additional circuit area, making them inefficient for high-frequency digital designs.
Innovation Solution
Implement stripe-based self-gating by partitioning the circuit into stages, self-gating only the first stage of each stripe, and using a change detect signal to enable clocking for subsequent stages, thereby reducing power consumption without increasing circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If self-gating circuits are implemented for each stage of retiming pipeline, then power consumption is reduced, but circuit area increases
Solution Approach 1:
The circuit is divided into stripes, with only the first stage of each stripe implementing self-gating circuitry. Subsequent stages within the same stripe share the change detect signal from the first stage, eliminating the need for duplicate self-gating circuits in each stage while maintaining power savings.
Solution Approach 2:
Multiple stages within a stripe share a common change detect signal generated by the first stage's self-gating circuitry. This merging approach allows one self-gating circuit to control clocking for multiple stages, reducing total circuit area while achieving power consumption reduction across all stages in the stripe.
2Loss of energy
If clock gating is implemented for each stage, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The change detect signal generated by the first stage's self-gating circuitry serves multiple functions: it controls clocking for the first stage and is distributed to control clocking for all subsequent stages within the stripe. This multi-functionality reduces the need for separate control circuits in each stage, simplifying the overall device while maintaining power savings.
3Loss of energy
If self-gating circuitry is added to reduce power consumption, then energy efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The circuit is organized into stripes where self-gating circuitry is segmented to appear only at the first stage of each stripe. This segmentation reduces the total quantity of self-gating circuits that need to be manufactured and placed, simplifying the manufacturing process while maintaining energy efficiency benefits across all stages through signal sharing.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Systems, apparatuses, and methods for implementing stripe-based self-gating and change detect signal propagation for retiming pipelines are disclosed. A circuit includes one or more stripes, with each stripe including a plurality of stages of registers, with each stage only receiving input signals from the preceding stage. For a given stripe, the first stage of registers are self-gated to reduce power consumption by only clocking a group of registers when any of their input signals change. The self-gating signals of the first stage of registers are combined together to create a change detect signal which is passed through a register and provided to a second stage of registers as a clock-enable signal. Accordingly, the second stage registers are only clocked when the change detect signal indicates a change will be forwarded from the first stage. This reduces power consumption for the second stage without causing the area increase associated with self-gating circuitry.