Memory Timing-Drift Calibration with Ring Oscillator Feedback
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Solution Overview
Problem
Integrated circuit devices, particularly memory devices, face significant timing drift due to temperature changes, leading to inaccuracies in clock distribution circuits, especially when transitioning between power states, which existing technologies fail to adequately address.
Innovation Solution
A system that includes a memory device with an oscillator circuit to measure frequency changes, allowing a memory controller to determine and calibrate timing drift by using a ring oscillator and measurement circuit to derive timing parameters, enabling dynamic adjustment of calibration intervals based on measured frequency changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the memory device operates in low-power state with idle ranks shut down, then power consumption is reduced, but timing drift occurs due to temperature changes during state transitions
Solution Approach 1:
The system performs preliminary timing calibration by measuring oscillator frequency before state transitions occur. The memory controller stores calibration data and applies it when transitioning between active and low-power states, preventing timing drift before it affects signal integrity.
Solution Approach 2:
The system continuously monitors oscillator frequency to detect timing drift caused by temperature changes. Based on this feedback, the memory controller dynamically adjusts calibration intervals and applies compensation values to maintain accurate timing relationships during power state transitions.
2Measurement precision
If frequent timing calibration is performed to maintain accuracy, then timing precision is improved, but power consumption increases
Solution Approach 1:
The system dynamically adjusts calibration intervals based on operating conditions such as temperature-drift-rate and signal timing measurements. Calibration frequency increases when timing drift is detected and decreases when stability is maintained, optimizing the balance between precision and power consumption.
Solution Approach 2:
The system changes calibration parameters adaptively by measuring oscillator frequency and determining timing drift values. Based on these measurements, the memory controller adjusts calibration timing and compensation values to maintain accuracy while minimizing unnecessary calibration operations that would increase power consumption.
3Device complexity
If the system uses fixed calibration intervals, then implementation simplicity is maintained, but timing accuracy deteriorates under varying temperature conditions
Solution Approach 1:
The system performs self-calibration by automatically measuring its own oscillator frequency and detecting timing drift. The memory controller autonomously determines when calibration is needed and applies compensation without external intervention, adapting to temperature changes while maintaining manageable complexity.
4Speed
If the memory device transitions quickly between power states, then operational speed is improved, but timing drift increases due to rapid temperature changes
Solution Approach 1:
The system performs preliminary frequency measurement and timing calibration before rapid state transitions. By preparing calibration data in advance and applying it proactively during transitions, the system maintains timing stability even during quick power state changes that cause rapid temperature variations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively mitigates timing drift by allowing for adaptive calibration intervals, reducing power consumption and maintaining accurate signal timings across temperature changes, thereby enhancing the reliability of memory systems.
Implementation Method 1
This large temperature-drift-rate can cause a significant timing drift over a short period of time, for example, because of the temperature sensitivity of clock distribution circuits (ps/deg C.) in a memory device.
Implementation Method 2
due to self-heating when transitioning from a low-power state to an active state
Implementation Method 3
self-cooling when transitioning from an active state to a low-power state
Data Source
AI summary
The disclosed embodiments relate to components of a memory system that support timing-drift calibration. In specific embodiments, this memory system contains a memory device (or multiple devices) which includes a clock distribution circuit and an oscillator circuit which can generate a frequency, wherein a change in the frequency is indicative of a timing drift of the clock distribution circuit. The memory device also includes a measurement circuit which is configured to measure the frequency of the oscillator circuit. Additionally, the memory system contains a memory controller which can transmit a request to the memory device to trigger the memory device to measure the frequency of the oscillator circuit. The memory controller is also configured to receive the measured frequency from the memory device and uses the measured frequency to determine the timing drift in the memory device.