Phase Shift Feedback Circuit for DRAM Data-Clock Alignment
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Solution Overview
Problem
Current DRAM standards lack a mechanism for returning phase alignment information from the receiving memory device to the memory controller, leading to increased complexity and cost in adjusting phase shifts between data and clock signals, especially at high data rates, which can result in higher error rates due to unforeseen delays.
Innovation Solution
A method and device configuration that involves transmitting test signals with varying phase shifts, detecting errors, and calculating an error detection code to adjust the phase shift optimally, using a microelectronic device with data signal drivers, error detecting code receivers, and phase shifting circuits to minimize errors in data detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanism for returning phase alignment information is implemented, then phase shift adjustment accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the receiving device detects phase alignment by transmitting test data patterns and comparing received patterns with expected patterns. The receiving device generates phase alignment information and returns it to the sending device, enabling automatic phase shift adjustment without requiring complex additional circuitry beyond standard memory operations.
Solution Approach 2:
The receiving device performs self-diagnosis by autonomously detecting phase alignment issues through test data transmission and comparison. The device automatically generates and returns phase alignment information without requiring external intervention or complex dedicated detection circuitry, utilizing existing memory read/write operations for the detection process.
2Measurement precision
If test data patterns are transmitted repeatedly to detect phase alignment, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent performs phase alignment detection during idle periods or when memory is not being actively used for application data. Test data patterns are transmitted and analyzed in advance before normal operation begins, or during transitions between operations, thereby obtaining phase alignment information without delaying critical data processing tasks.
Solution Approach 2:
The patent transmits test data patterns selectively rather than continuously - only when phase re-calibration is needed or during idle periods. This partial action approach achieves sufficient measurement precision for phase alignment detection without the time penalty of continuous testing, balancing accuracy requirements with operational efficiency.
3Adaptability or versatility
If memory space is used for storing test data patterns, then adaptability is improved, but application data storage capacity decreases
Solution Approach 1:
The patent uses memory space for test data patterns only periodically - during phase calibration sequences - rather than continuously. During normal operation, the memory is dedicated to application data. This periodic alternation allows the system to maintain full memory capacity for applications while still enabling phase alignment detection when needed.
Solution Approach 2:
The patent temporarily uses memory space for test data patterns during calibration operations, then discards these test patterns and recovers the full memory capacity for application data. The phase alignment information obtained from test patterns is stored in separate registers or control structures, not in the main memory space used for applications.
4Measurement precision
If complex computation is performed to identify phase window, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent replaces complex computational analysis with a simpler pattern comparison approach. Instead of performing elaborate computations to identify the phase window, the system transmits known test data patterns and compares the received patterns directly with expected patterns, using the discrepancies to determine phase alignment. This substitution of mechanical/computational processes with direct comparison operations maintains measurement precision while significantly improving computation speed.
Data Source
AI summary
Method and system of adjusting a first phase shift between a first data signal and a clock signal at a sending device. First and second test signals representing first and second test data, respectively, are transmitted to a receiving device. The test signals have respective phase shifts relative to the clock signal. An error detection code is calculated from first and second received data carried by the transmitted signals. The error detection code is transmitted from the receiving device to the sending device. An estimated first received data is calculated from the error detection code, wherein the estimated first received data are calculated under the assumption that the second received data are identical to the second test data. The first phase shift is adjusted on the basis of a comparison of the estimated first received data and the first test data.