Semiconductor Power-Down Signal Generation with Internal Refresh Control
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Solution Overview
Problem
Semiconductor devices, particularly DRAM devices, face challenges in maintaining data integrity during power-down modes and require efficient initialization and refresh operations without external control signals.
Innovation Solution
The semiconductor device incorporates a power-down signal generation circuit and a refresh signal generation circuit that operate based on internal command decoding, enabling power-down and refresh operations independently of external signals, with specific timing and signal generation circuits to manage these states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the semiconductor device enters power-down mode to minimize driving current, then power consumption is reduced, but data retention reliability deteriorates
Solution Approach 1:
The refresh operation is performed before the power-down mode fully takes effect to pre-charge the memory cells. The refresh signal is generated in advance to ensure data is rewritten prior to the termination of internal voltages, preventing data loss during power-down
Solution Approach 2:
The refresh operation is implemented as a periodic action that occurs at specific intervals before power-down mode activation. The refresh control circuit periodically generates refresh signals to maintain data integrity, creating a rhythmic pattern of refresh operations that ensures reliability while enabling power savings
2Reliability
If the semiconductor device performs refresh operations to prevent data loss, then data retention reliability is improved, but power consumption increases
Solution Approach 1:
Instead of continuous refresh operations, the patent implements partial refresh actions only when needed - specifically when transitioning to power-down mode or when data integrity is at risk. This partial action approach maintains reliability while minimizing unnecessary power consumption during normal operation
Solution Approach 2:
Refresh operations are performed in advance before power-down mode activation rather than continuously. This preliminary action ensures data is saved before the high-power state terminates, eliminating the need for sustained refresh operations and reducing overall power consumption
3Ease of operation
If the semiconductor device uses external control signals for power-down and refresh operations, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The power-down and refresh control functions are merged into a single integrated refresh control circuit that automatically generates both power-down signals and refresh signals based on internal state detection. This merging eliminates the need for separate external control signals while maintaining operational ease
Solution Approach 2:
The refresh control circuit performs self-service by automatically detecting internal voltage states and generating appropriate control signals without external intervention. The circuit monitors its own operation status and autonomously initiates refresh or power-down sequences, reducing the burden on external controllers
Data Source
AI summary
A semiconductor device may be provided. The semiconductor device may include a power-down signal generation circuit and a refresh signal generation circuit. The power-down signal generation circuit may be configured to generate a power-down signal which is enabled during a power-down operation period based on a multi-operation signal that is generated by decoding commands. The refresh signal generation circuit may be configured to generate a refresh signal which is enabled during a refresh operation period based on the multi-operation signal and an operation selection signal.