Self-Refresh Control Device for DRAM Current Reduction
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Solution Overview
Problem
Dynamic random access memories (DRAMs) in mobile devices experience unnecessary current consumption due to frequent self-refresh operations, which can lead to data loss and reduced battery life.
Innovation Solution
A self-refresh control device that latches a clock enable signal to generate an oscillation enable signal, selects between oscillation enable and self-refresh command signals to produce an oscillation end signal, and uses this to control the generation of self-refresh signals, preventing additional self-refresh operations during a specific pulse period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If self-refresh operations are performed frequently to prevent data loss, then data reliability is improved, but current consumption increases
Solution Approach 1:
The patent implements periodic self-refresh operations by controlling the oscillator to generate refresh signals only during specific entry periods rather than continuously. The enable signal generation circuit latches the clock enable signal for a predetermined time to create periodic oscillation enable signals, which activate the oscillator only during designated refresh intervals. This periodic activation ensures data is refreshed sufficiently to maintain reliability while significantly reducing current consumption compared to continuous refresh operations.
2Duration of action of stationary object
If self-refresh operations are performed continuously to maintain data, then data retention is improved, but battery life deteriorates
Solution Approach 1:
The patent performs preliminary actions by latching the clock enable signal in advance to generate oscillation enable signals before the actual self-refresh operations commence. The enable signal generation circuit prepares the oscillation enable signals during specific entry periods, allowing the oscillator to be activated only when necessary. This preliminary control mechanism ensures data retention is maintained through timely refresh operations while extending battery life by eliminating unnecessary continuous operation.
3Reliability
If the oscillator generates self-refresh signals repeatedly during entry period, then data refresh completeness is improved, but current consumption increases
Solution Approach 1:
The patent applies local quality by making the oscillator's operation conditional and location-specific in time. The end signal generation circuit selectively activates the oscillator only during specific entry periods when refresh operations are actually needed, rather than allowing repeated generation throughout the entire clock cycle. This localized activation ensures refresh completeness is achieved during critical periods while minimizing energy waste during non-critical periods when the oscillator remains inactive.
Data Source
AI summary
A self-refresh control device may be provided. The self-refresh control device may include a refresh signal output circuit configured to generate self-refresh signals with an oscillator and provide a refresh signal. The self-refresh control device may begin a self-refresh mode in response to a clock enable signal and a self-refresh signal within a self-refresh entry period, and may prevent performance of a new self-refresh operation by delaying an additional self-refresh signal until after the self-refresh entry period has ended.