DRAM Command Transfer Over a Single Clock Signal
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Solution Overview
Problem
Conventional DRAM memory devices require separate clock signals for command and data interfaces, leading to increased complexity, power consumption, and latency due to synchronizing and training circuitry, which consumes additional I/O pins and prolongs exit times from low-power states.
Innovation Solution
A method for transferring commands and data using a single clock signal, eliminating the need for internal synchronizing and training circuitry by synchronizing the memory device to a first clock edge and using a synchronization signal to establish command start points, allowing a single receiver and I/O pin for clock signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If separate clock signals are used for command and data interfaces, then data transfer speed can be optimized, but device complexity and power consumption increase due to synchronizing and training circuitry
Solution Approach 1:
The patent merges the command interface clock and data interface clock into a single unified clock signal. This eliminates the need for separate synchronizing and training circuitry that would otherwise be required to coordinate two different clock signals, thereby reducing internal circuit complexity while maintaining optimized data transfer speeds through the single clock's ability to synchronize both command and data operations.
Solution Approach 2:
The single clock signal serves multiple functions simultaneously: it clocks both the command interface and the data interface, and it also provides the synchronization signal for command transfer. This multi-functional design eliminates the need for dedicated separate clock circuits and reduces overall device complexity while preserving high-speed data transfer capability.
2Speed
If separate clock signals are used for command and data interfaces, then data transfer speed can be optimized, but power consumption increases due to additional synchronizing and training circuitry
Solution Approach 1:
The patent merges the command interface clock and data interface clock into a single unified clock signal. This eliminates the need for separate synchronizing and training circuitry that would otherwise be required to coordinate two different clock signals, thereby reducing internal circuit complexity while maintaining optimized data transfer speeds through the single clock's ability to synchronize both command and data operations.
Solution Approach 2:
The patent extracts and eliminates the need for separate synchronizing and training circuitry by using a single clock signal that inherently provides synchronization for both command and data interfaces. This removal of unnecessary circuit components directly reduces power consumption while preserving high-speed data transfer capability.
3Reliability
If synchronizing and training circuitry is used, then clock signal synchronization can be achieved, but I/O pin usage increases and exit time from low-power states prolongs
Solution Approach 1:
The patent merges the clock signal and synchronization signal into a single unified signal path. The single clock signal simultaneously provides timing for data transfers and synchronization for command interfaces, eliminating the need for separate synchronizing and training circuitry. This integration eliminates additional I/O pins and reduces exit time from low-power states by removing the training procedure requirement.
Solution Approach 2:
The patent extracts and eliminates the need for separate synchronizing and training circuitry by using a single clock signal that inherently provides synchronization for both command and data interfaces. This removal of unnecessary circuit components directly reduces power consumption while preserving high-speed data transfer capability.
Data Source
AI summary
Various embodiments include a memory device that is capable of transferring both commands and data via a single clock signal input. In order to initialize the memory device to receive commands, a memory controller transmits a synchronization command to the memory device. The synchronization command establishes command start points that identify the beginning clock cycle of a command that is transferred to the memory device over multiple clock cycles. Thereafter, the memory controller transmits subsequent commands to the memory device according to a predetermined command length. The predetermined command length is based on the number of clock cycles needed to transfer each command to the memory device. Adjacent command start points are separated from one another by the predetermined command length. In this manner, the memory device avoids the need for a second lower speed clock signal for transferring commands to the memory device.