DRAM Refresh Control via Command Decoder and Period Signal Circuit
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Solution Overview
Problem
Dynamic random access memory (DRAM) semiconductor devices require periodic refresh operations to prevent data loss due to current leakage, which complicates data retention and increases power consumption.
Innovation Solution
A semiconductor device incorporating a command decoder and period signal generation circuit to manage internal chip selection and control signals, enabling efficient generation of entry and exit commands for refresh operations, thereby stabilizing internal operations and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic refresh operations are performed to prevent data loss in DRAM devices, then data retention is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic refresh operations through a counter that generates refresh commands at predetermined intervals. The counter is reset by refresh entry commands and counts up to a threshold value, triggering refresh exit commands periodically. This ensures data retention through regular refresh cycles while minimizing power consumption by performing refresh operations only when necessary, rather than continuously.
2Reliability
If refresh operations are continuously performed to maintain data, then data retention is improved, but operational efficiency deteriorates
Solution Approach 1:
The patent employs a feedback mechanism where the counter monitors the number of refresh operations performed and provides feedback to the command decoder. When the counter reaches a predetermined threshold value, it triggers a refresh exit command to stop further refresh operations. This feedback-controlled approach ensures data retention through adequate refresh operations while preventing excessive refreshing that would degrade operational efficiency.
3Ease of operation
If multiple internal control signals are used to manage chip selection and operations, then operational control is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple internal control signals (first internal chip selection signal, second internal chip selection signal, first internal control signal, and second internal control signal) into a unified control framework. The command decoder integrates these signals to generate coordinated entry and exit commands, reducing the need for separate complex control circuits for each signal while maintaining precise operational control through the consolidated decoding logic.
Data Source
AI summary
A semiconductor device includes a command decoder and a period signal generation circuit. The command decoder generates a first entry command and a first exit command based on a first internal chip selection signal and a first internal control signal and generates a second entry command and a second exit command based on a second internal chip selection signal and a second internal control signal. The period signal generation circuit generates a period signal based on the first entry command, the second entry command, the first exit command, the second exit command, and the period signal.