Command Window Generator for DRAM Power Reduction
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Solution Overview
Problem
In dynamic random access memory (DRAM), the wide write command window due to high write latency leads to unnecessary driving of the data input circuit, resulting in increased current consumption and power consumption.
Innovation Solution
A command window generator is introduced, comprising a clock freezer circuit, first and second circuits, and a delay measure circuit, which generates a command window by compensating for delay times on the data write and read paths, allowing the data input and output circuits to latch data only when necessary, reducing standby power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the write command window is widened to accommodate high write latency, then data can be latched without missing, but the data input circuit is driven unnecessarily causing increased current consumption
Solution Approach 1:
The patent applies dynamics by making the command window width adjustable rather than fixed. The control circuit dynamically configures the command window generator to produce different window widths based on operating conditions, allowing the system to optimize between reliability and power consumption by narrowing the window when high latency isn't required
Solution Approach 2:
The patent changes the parameter of command window width from a static value to a variable parameter that can be adjusted. The control circuit modifies the window generation parameters based on write latency conditions, enabling the system to adapt the window width to match actual data availability timing and reduce unnecessary circuit activation
2Reliability
If the command window is made wider to ensure data availability, then data can be processed without loss, but power consumption increases due to extended circuit operation
Solution Approach 1:
The system dynamically adjusts the command window width based on actual write latency measurements. When latency is low, the window is narrowed to minimize standby power consumption. When latency is high, the window expands to ensure complete data capture, thus adapting power consumption to actual operational needs rather than maintaining a constant wide window
Solution Approach 2:
The control circuit implements feedback by monitoring write latency conditions and using this information to adjust the command window width. This closed-loop control ensures the window is only as wide as necessary to capture all data, preventing unnecessary power consumption while maintaining data processing reliability
Data Source
AI summary
A memory device including a command window generator is provided. The command window generator is configured to generate a delay signal by converting a delay time between a clock signal input to a write path circuit and a clock signal output to a write path replica circuit into a number of cycles of an internal clock signal, by using the write path circuit and the write path replica circuit, and generate a command window to correspond to a data window using the delay signal. The delay window may correspond to a burst length of write data.