Semiconductor Device Power Saving State Control
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Solution Overview
Problem
Semiconductor devices, particularly those incorporating NAND flash memory and DRAM, face challenges in reducing power consumption, as existing technologies do not effectively manage power transitions and refreshing operations in power saving modes, leading to inefficiencies in energy usage.
Innovation Solution
A semiconductor device configuration that includes a nonvolatile memory, a volatile memory, and a controller, which transitions a part of the volatile memory to a self-refresh mode upon receiving a power stop request, allowing for independent refreshing of storage areas and optimizing power supply to reduce overall power consumption by entering a super power saving state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the semiconductor device enters a power saving mode to reduce power consumption, then power consumption is reduced, but data retention in volatile memory becomes problematic
Solution Approach 1:
The volatile memory is divided into multiple storage areas, with at least one area maintained in normal operation mode while others enter self-refresh mode. This segmentation allows different parts of the memory to have different power states, enabling data retention in critical areas while reducing power consumption in less critical areas.
Solution Approach 2:
Different storage areas of the volatile memory are assigned different operational characteristics - some areas maintain full functionality and data retention while others enter lower power states. This local differentiation of quality allows the system to optimize power consumption without compromising overall data retention reliability.
2Reliability
If all storage areas of volatile memory are refreshed continuously to ensure data retention, then data retention is maintained, but power consumption increases
Solution Approach 1:
The memory system implements periodic self-refresh operations only for specific storage areas that require data retention, rather than continuous refreshing of all areas. This periodic action in selected areas significantly reduces power consumption while maintaining data integrity where needed.
Solution Approach 2:
Instead of applying full refreshing operations to all storage areas, the system applies partial refreshing action only to the extent necessary for data retention in critical areas, leaving other areas in lower power states without continuous refreshing.
3Use of energy by moving object
If the semiconductor device transitions to a super power saving state by stopping power supply to nonvolatile memory, then power consumption is significantly reduced, but recovery time increases
Solution Approach 1:
Before transitioning to the super power saving state, the system performs preliminary actions by maintaining certain volatile memory areas in a ready state with retained data. This preliminary preparation allows for faster recovery since critical data is already available in the volatile memory, reducing the time needed to resume operations after power supply is restored.
Data Source
AI summary
According to one embodiment, a semiconductor device includes a nonvolatile memory, a volatile memory, and a controller. The controller is configured to transition a part of the volatile memory to a self-refresh mode when a request for stopping supplying of power to the nonvolatile memory is received.