Memory Command Path Delay Calibration for Write Latency Alignment
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Solution Overview
Problem
High-frequency memory clock signals in semiconductor memory systems pose challenges in maintaining proper timing of internal clock, data, and command signals, leading to issues like write latency and power consumption, especially in multi-data rate memories where data rates exceed clock frequencies, causing propagation delays to vary with power, voltage, and temperature changes.
Innovation Solution
A timing calibration and adjustment circuit is implemented to align command and data signals with clock edges, using clock buffers and latency shift circuits to add delays and ensure correct timing margins, while minimizing continuous power consumption by using phase-aligned signals and adaptive delay adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If delays and counter circuitry are run continuously to maintain timing of internal signals, then timing accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic calibration of delay circuits at specific intervals (e.g., when write latency is changed) rather than continuous operation. The delay calibration circuit operates periodically to adjust timing parameters, maintaining accuracy while consuming power only when necessary, not continuously during all memory operations.
Solution Approach 2:
The system uses self-calibration mechanisms where the memory device automatically adjusts its own timing parameters through internal delay calibration circuits. The device monitors its own timing requirements and performs self-adjustment without external intervention, reducing the need for continuous external control and associated power consumption.
2Reliability
If propagation delay of internal paths is increased to accommodate write latency, then timing margins are improved, but variations due to power, voltage, and temperature changes negatively affect timing
Solution Approach 1:
The patent implements feedback mechanisms where the actual timing performance is monitored and used to adjust delay circuit parameters. The system measures the actual propagation delays under varying conditions and dynamically adjusts the delay circuits to compensate for deviations, maintaining stable timing margins despite changes in power, voltage, or temperature.
Solution Approach 2:
The system dynamically changes delay parameters based on operating conditions. The delay calibration circuit adjusts timing parameters in response to detected variations in power, voltage, or temperature, modifying the delay characteristics to maintain optimal timing margins under different environmental conditions.
3Productivity
If multi-data rate operation is implemented to increase data rate beyond clock frequency, then productivity is improved, but timing domain crossing complexity increases
Solution Approach 1:
The patent introduces intermediary synchronization circuits and timing domain crossing circuits that act as mediators between different clock domains. These intermediary circuits translate and synchronize signals between the slower command clock domain and the faster data clock domain, enabling multi-data rate operation while managing the complexity through structured intermediate stages.
Solution Approach 2:
The system segments the timing domain crossing function into separate, modular circuits: command path delay calibration circuits for the command domain, data path delay calibration circuits for the data domain, and dedicated timing domain crossing circuits. This segmentation allows each segment to be optimized independently, managing overall complexity through modular design.
Data Source
AI summary
Command paths, apparatuses, memories, and methods for providing an internal command to a data path are disclosed. In an example method, a command is received and propagated through a command path to provide an internal command. Further included in the method is determining a difference between a latency value and a path delay difference, the path delay difference representing a modeled path delay difference between the command path and the data path measured in terms of a number of clock periods. The propagation of the command through the command path to the data path is delayed by a delay based at least in part on the difference between the latency value and the path delay difference. The internal command is provided to the data path responsive to an internal clock signal.