PHY Clock Domain Staggering for Low-Latency Power-Down Exit
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Solution Overview
Problem
Modern integrated circuits face challenges in efficiently managing power consumption during transitions out of power-down modes, particularly due to the differing clock domains requiring simultaneous reactivation, which leads to unnecessary power consumption and increased latency.
Innovation Solution
Implementing a staggered power-down exit strategy for the control and data clock domains, where the data clock domain is activated only when necessary based on specific events or commands, such as the detection of memory core access, using separate clock enable signals to minimize unnecessary power usage and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both control clock domain and data clock domain are reactivated simultaneously on power-down exit, then all necessary circuits are available immediately, but power consumption increases and latency is extended
Solution Approach 1:
The patent segments the clock domain reactivation into two distinct phases: first reactivating the control clock domain circuits, then selectively reactivating the data clock domain circuits based on whether data transactions are detected. This segmentation allows the system to avoid unnecessary power consumption in the data clock domain while ensuring control functions are available immediately upon power-down exit.
Solution Approach 2:
The control clock domain is reactivated in advance before the data clock domain. By preliminarily activating the control clock domain first, the system ensures that control functions are available immediately while delaying data clock domain activation until it is actually needed, thus reducing overall power consumption without compromising reliability.
2Productivity
If data clock domain is reactivated immediately, then data transactions can proceed without delay, but unnecessary power is consumed when no data transactions are pending
Solution Approach 1:
The patent implements dynamic reactivation of the data clock domain based on real-time detection of data transaction requirements. Instead of static immediate reactivation, the system dynamically adjusts whether to activate the data clock domain by monitoring for pending data transactions, thereby optimizing the balance between productivity and energy loss.
Solution Approach 2:
The system applies partial action by selectively activating only the necessary portions of the clock domains. Rather than fully reactivating both domains simultaneously, it activates the control clock domain completely and the data clock domain only when needed, avoiding excessive power consumption while maintaining sufficient productivity.
3Use of energy by stationary object
If control clock domain is activated first with staggered timing, then power consumption is reduced, but data transaction latency may increase
Solution Approach 1:
The system uses self-service mechanisms where the detection of data transaction requirements triggers the activation of the data clock domain. This self-triggering approach ensures that the data clock domain is activated at the optimal moment - immediately when needed - thereby minimizing latency while still benefiting from the power savings of delayed activation.
Data Source
AI summary
An integrated circuit includes a physical layer interface having a control timing domain and a data timing domain, and circuits that enable the control timing domain during a change in power conservation mode in response to a first event, and that enable the data timing domain in response to a second event. The control timing domain can include interface circuits coupled to a command and address path, and the data timing domain can include interface circuits coupled to a data path.