Semiconductor Memory Clock Phase Alignment for Timing Margin Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor memory devices face challenges in maintaining synchronized operation due to differences in delay amounts and impedance mismatches between system clock and inverted system clock signals, leading to voltage level discrepancies and reduced operational timing margins.
Innovation Solution
A semiconductor memory device circuit that adjusts the voltage level of the intersection of system and inverted system clock signals to match the reference signal, using clock input units, delay units, and phase comparators to control delay and generate delay control signals, ensuring synchronized operation across multiple memory devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transmission lines are used to transfer system clock and inverted system clock signals to multiple semiconductor memory devices, then data can be distributed to multiple devices, but delay amounts and impedance mismatches cause voltage level discrepancies and timing errors
Solution Approach 1:
Each semiconductor memory device is equipped with a dedicated voltage level adjustment circuit that locally compensates for delay amounts and impedance mismatches specific to its position in the module. This allows each device to receive and adjust clock signals according to its individual characteristics, maintaining synchronization accuracy across the entire module despite variations in transmission line lengths and impedances.
Solution Approach 2:
The voltage level adjustment circuit uses feedback mechanisms to detect voltage level discrepancies caused by transmission delays and impedance mismatches, then automatically adjusts the clock signal timing to compensate for these variations. This feedback-based adjustment ensures that each memory device operates with accurately synchronized clock signals despite physical variations in the module layout.
2Quantity of substance
If multiple semiconductor memory devices are arranged in a module with different transmission line lengths, then module capacity is increased, but delay amount differences cause timing margin reduction
Solution Approach 1:
Instead of requiring all transmission lines to have identical lengths and characteristics, each memory device is provided with a voltage level adjustment circuit that locally compensates for its specific transmission line characteristics. This allows the module to accommodate devices at different positions with varying transmission line lengths while maintaining adequate timing margins through individualized adjustment.
Solution Approach 2:
The voltage level adjustment circuit dynamically adapts to the specific timing characteristics of each memory device's transmission lines, allowing the system to maintain optimal timing margins regardless of the number or position of devices in the module. This dynamic adjustment capability enables the module to scale in capacity while preserving timing precision.
3Device complexity
If impedance matching is not performed between transmission lines and memory device inputs, then device complexity is reduced, but voltage level discrepancies increase
Solution Approach 1:
The voltage level adjustment function is extracted from the transmission line design and implemented as a separate, dedicated circuit within each memory device. This allows the transmission lines to remain simple without complex impedance matching requirements, while the extracted voltage level adjustment circuit compensates for impedance mismatches and delay variations, maintaining voltage level accuracy without increasing overall system complexity.
Data Source
AI summary
A semiconductor memory device includes a first clock input unit for generating a first clock signal based on a signal at an intersection of a system clock signal and an inverted system clock signal; a second input unit for generating a second clock signal based on a signal at an intersection of the system clock signal and a reference signal; a third input unit for generating a third clock signal based on a signal at an intersection of the inverted system clock signal and the reference signal; a delay unit for generating a delay clock signal by delaying the first clock signal in response to a delay control signal; and a clock delay control unit for generating the delay control signal in response to a phase difference between the second clock signal and the delay clock signal or a phase difference between the third clock signal and the delay clock signal.