Memory System Delay Tracking Using Mode-Specific Oscillators
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Solution Overview
Problem
The current fifth-generation low-power DDR (LPDDR5) standard lacks specifications for efficiently using WCK2DQI or WCK2DQO oscillators for delay tracking in different frequency modes, which affects the performance of writing and reading operations.
Innovation Solution
A delay tracking method and memory system that select and enable low-frequency-mode (LFM) and high-frequency-mode (HFM) oscillators using Multipurpose Command (MPC) or Mode Register Operand (MR OP) to obtain and store delay values, allowing for efficient delay tracking when switching between frequency modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the current LPDDR5 standard uses WCK2DQI or WCK2DQO oscillators for delay tracking without specifying efficient usage in different frequency modes, then delay tracking can be performed, but the performance is suboptimal and continuous oscillator enabling is required during mode changes
Solution Approach 1:
The patent applies preliminary action by pre-obtaining and storing delay values for both LFM and HFM modes before mode switching occurs. The memory controller stores HFM delay values in a first register and LFM delay values in a second register, so that when mode switching happens, the appropriate pre-calculated delay value is already available for immediate use, eliminating the need for continuous oscillator enabling during transitions.
Solution Approach 2:
The patent implements parameter changes by selectively enabling different oscillators based on the operating frequency mode. When in HFM, the WCK2DQO oscillator is enabled to obtain HFM delay values; when in LFM, the WCK2DQI oscillator is enabled to obtain LFM delay values. This dynamic parameter adjustment optimizes delay tracking efficiency for each frequency mode while reducing unnecessary oscillator operation during mode changes.
2Reliability
If oscillators are continuously enabled for delay tracking during frequency mode switching, then accurate delay values can be obtained, but power consumption increases
Solution Approach 1:
The patent applies periodic action by enabling oscillators only when needed for specific frequency modes rather than continuously. The WCK2DQO oscillator is enabled periodically when HFM operation is required, and the WCK2DQI oscillator is enabled periodically when LFM operation is required. This periodic enabling maintains delay tracking accuracy while significantly reducing power consumption compared to continuous oscillator operation.
Solution Approach 2:
The patent changes the operational parameters of the oscillators based on the frequency mode. By adjusting which oscillator is active (WCK2DQO for HFM, WCK2DQI for LFM) and when it is enabled, the system maintains reliable delay tracking accuracy for each mode while optimizing power consumption by avoiding unnecessary oscillator operation during mode transitions and when the other frequency mode is active.
3Use of energy by moving object
If the system switches between LFM and HFM modes dynamically, then power efficiency is improved, but delay tracking complexity increases due to lack of specifications
Solution Approach 1:
The patent reduces control complexity by performing preliminary actions of obtaining and storing delay values for both frequency modes before switching occurs. The memory controller proactively stores HFM delay values in a first register and LFM delay values in a second register, so that during dynamic mode switching, the system simply retrieves the appropriate pre-stored value rather than performing complex real-time calculations or oscillator management, thereby maintaining power efficiency while simplifying control.
Solution Approach 2:
The patent introduces registers as intermediary storage elements between the oscillators and the delay tracking logic. The first register stores HFM delay values and the second register stores LFM delay values, acting as intermediaries that buffer the delay values. This intermediary approach simplifies the control logic during mode switching by decoupling the oscillator operation from the delay value retrieval, making the dynamic frequency mode switching more manageable while maintaining power efficiency.
Data Source
AI summary
A delay tracking method and a memory system are provided. The delay tracking method is applied to a memory system supporting a low-frequency-mode (LFM) and a high-frequency-mode (HFM) of an operating clock. The delay tracking method includes the steps of selecting a LFM oscillator for obtaining a LFM delay value when the operating clock is in the HFM; and selecting a HFM oscillator for obtaining a HFM delay value when the operating clock is in the LFM.