Internal Write Leveling Circuitry for Memory Devices
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Solution Overview
Problem
In semiconductor memory devices, internal write leveling struggles to synchronize internal write signals with data strobe signals, often resulting in late signal launches that can lead to increased power consumption when attempting to match the faster data strobe signal path, and existing solutions either delay the internal data strobe or increase power usage.
Innovation Solution
The implementation of internal write signal circuitry that launches the internal write signal earlier than the programmed CAS Write Latency, using a combination of flip-flops and clock shifting to adjust the signal timing, allowing the internal data strobe to capture the write signal properly without artificial delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal write signal is launched at the programmed CAS Write Latency, then the timing follows the standard protocol, but the signal arrives late relative to the faster data strobe signal path
Solution Approach 1:
The internal write signal is launched earlier than the programmed CAS Write Latency to compensate for the slower path. This preliminary action ensures that the signal arrives at the same time as the data strobe signal, resolving the timing mismatch without requiring delays to the faster data strobe path.
2Reliability
If the internal data strobe is delayed to match the slower internal write signal path, then synchronization is achieved, but power consumption increases
Solution Approach 1:
Instead of delaying the faster data strobe signal to match the slower internal write signal, the invention inverts the approach by launching the internal write signal earlier. This avoids the power consumption penalty associated with delaying the data strobe while achieving the same synchronization goal.
3Reliability
If the internal write signal is launched earlier to compensate for the slower path, then synchronization with data strobe is improved, but the launch timing deviates from the programmed CAS Write Latency
Solution Approach 1:
A timing adjustment mechanism acts as an intermediary between the programmed CAS Write Latency and the actual internal write signal launch. This intermediary component enables the signal to be launched at the correct adjusted time for synchronization while maintaining compatibility with the standard timing protocol.
Data Source
AI summary
A host device and memory device function together to perform internal write leveling of a data strobe with a write command within the memory device. The memory device includes a command interface configured to receive write commands from the host device. The memory device also includes an input-output interface configured to receive the data strobe from the host device. The memory device also includes internal write circuitry configured to launch an internal write signal based at least in part on the write commands. The launch of the internal write signal is based at least in part on an indication from the host device that indicates when to launch the internal write signal relative to a cas write latency (CWL) for the memory device.