On-Die Thermal Sensor for Adaptive DRAM Refresh Control
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Solution Overview
Problem
Dynamic random access memory (DRAM) systems face challenges in accurately sensing internal temperatures to optimize refresh operations, leading to potential data loss and increased power consumption, especially in battery-operated systems and high-integration semiconductor devices.
Innovation Solution
An on-die thermal sensor (ODTS) is developed, comprising a temperature information code generation unit, flag signal logic determination unit, and self-refresh period change unit, which senses internal temperatures and adjusts refresh clock frequencies based on temperature variations, preventing incorrect temperature information and optimizing self-refresh operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refresh operation frequency is increased to prevent data loss, then data reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of refresh operation frequency based on detected temperature conditions. The refresh controller modifies the refresh period according to temperature, using shorter periods at higher temperatures and longer periods at lower temperatures, thereby optimizing the balance between data reliability and power consumption
Solution Approach 2:
The patent changes the refresh period parameter based on temperature detection. By detecting temperature conditions and adjusting the refresh period accordingly, the system adapts refresh operations to actual thermal states, preventing data loss while minimizing unnecessary refresh operations that consume power
2Use of energy by moving object
If temperature sensing accuracy is improved to optimize refresh operations, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The patent employs an on-die temperature sensor that is self-contained within the memory device, eliminating the need for external temperature sensing components. The sensor automatically detects temperature conditions and provides feedback to the refresh controller, enabling autonomous temperature-based refresh optimization without adding significant system complexity
Solution Approach 2:
The patent introduces a temperature sensor as an intermediary component that bridges the gap between physical temperature conditions and refresh operation control. This intermediary converts temperature into detectable signals that the refresh controller can use to adjust refresh timing, simplifying the overall control mechanism
3Use of energy by moving object
If refresh period is extended at low temperature to reduce power consumption, then power efficiency is improved, but data loss risk increases
Solution Approach 1:
The patent dynamically adjusts refresh period based on real-time temperature detection. At low temperatures where data retention is naturally longer, the system extends refresh periods to improve power efficiency. At high temperatures where data retention deteriorates faster, the system shortens refresh periods to maintain reliability, creating an adaptive balance between power efficiency and data protection
Data Source
AI summary
An on die thermal sensor (ODTS) for use in a semiconductor memory device includes: a temperature information code generation unit for sensing an internal temperature of the semiconductor memory device in response to first and second enable signals and for generating a temperature information code which includes the sensed temperature information; and a flag signal logic determination unit for generating a plurality of first flag signals having temperature information and determining whether the plurality of first flag signals have a predetermined logic level or a variable logic level in response to the first and second enable signals.