Multi-channel Self Refresh Device Shared Pulse Generator
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Solution Overview
Problem
Multi-channel semiconductor memory devices face challenges in controlling self-refresh operations due to increased area size and current consumption when each channel has a separate Temperature Compensated Self Refresh (TCSR) periodic pulse generator, and asynchronous self-refresh command signals can lead to defective cells during testing.
Innovation Solution
A multi-channel self-refresh device with a combination unit that generates a refresh enable signal from multiple self-refresh signals, a period generation circuit producing a self-refresh pulse signal, and PSRF controllers that activate refresh signals in response to specific self-refresh command signals, allowing for shared control of self-refresh pulses across channels and preventing defects during testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate TCSR periodic pulse generator is assigned to each channel, then self-refresh control reliability is improved, but area size and current consumption increase
Solution Approach 1:
Multiple channels share a single TCSR periodic pulse generator instead of each channel having a separate generator. The shared generator produces a common self-refresh pulse signal that is distributed to multiple channels through individual PSRF controllers, reducing the total area occupied by pulse generators while maintaining reliable self-refresh control for each channel
Solution Approach 2:
The system is divided into a shared TCSR periodic pulse generator and individual PSRF controllers for each channel. This segmentation allows the pulse generation function to be shared while maintaining independent control capability for each channel through its dedicated PSRF controller, balancing resource sharing with channel independence
2Reliability
If a separate TCSR periodic pulse generator is assigned to each channel, then self-refresh control reliability is improved, but current consumption increases
Solution Approach 1:
Multiple channels share a single TCSR periodic pulse generator instead of each channel having a separate generator. The shared generator produces a common self-refresh pulse signal that is distributed to multiple channels through individual PSRF controllers, reducing the total current consumption of pulse generators while maintaining reliable self-refresh control for each channel
Solution Approach 2:
The TCSR periodic pulse generator is designed as a universal circuit that can serve multiple channels simultaneously. This multi-functional design reduces redundant circuitry and current consumption while maintaining the ability to independently control self-refresh operations for each channel through the PSRF controllers
3Adaptability or versatility
If self refresh command signals are asynchronously input to multiple channels, then operational flexibility is improved, but defective cells may occur during testing
Solution Approach 1:
A test mode signal is introduced that can preemptively control the PSRF controllers before actual self-refresh operations begin. During test mode, the test mode signal overrides the asynchronous self-refresh command signals, ensuring that all channels receive synchronized control signals and preventing defective cells from occurring during testing while maintaining operational flexibility during normal operation
Data Source
AI summary
A multi-channel self refresh device may include period generation circuit configured to output a self refresh pulse signal having a predetermined time period in response to a refresh enable signal. The multi-channel self refresh device may include a channel region configured to activate a refresh signal in response to the self refresh pulse signal, when a self refresh command signal corresponding to a channel from among a plurality of self refresh command signals is activated.