Sequential Temperature Sensor for DRAM Power Management
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Solution Overview
Problem
Conventional temperature detectors for semiconductor devices, such as DRAM, are sensitive to semiconductor fabrication process changes, requiring time-consuming trimming tests and occupying significant chip area, especially as the number of branches increases, which complicates power management in battery-operated systems.
Innovation Solution
A temperature detector with a temperature sensor that generates tracking signals indicating temperature ranges, a control circuit that adjusts refresh rates in DRAM based on these signals, and a hysteresis characteristic to prevent malfunctions at temperature boundaries, using a configuration that includes a temperature sensitive unit and a tracking signal generation unit to compare detected temperatures with reference signals, allowing for efficient power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple branches are used in conventional temperature detectors to provide multiple detection temperature points, then temperature detection accuracy is improved, but chip area occupation increases significantly
Solution Approach 1:
The patent segments the temperature detection function into multiple sequential stages using a single branch. Instead of using multiple parallel branches simultaneously, the detector divides temperature detection into multiple temperature ranges and sequentially activates different detection circuits for different ranges, achieving multi-point detection with minimal chip area.
Solution Approach 2:
The patent implements dynamic switching between different temperature detection circuits based on the detected temperature range. A control circuit dynamically selects which detection circuit to activate, allowing the system to adapt its detection characteristics to the current temperature conditions while using only one physical branch structure.
2Measurement precision
If multiple branches are used in conventional temperature detectors, then temperature detection capability is improved, but trimming test time increases significantly
Solution Approach 1:
The patent segments the trimming process into sequential steps corresponding to different temperature ranges. Each detection circuit is trimmed independently during manufacturing, but only one circuit is active at a time during operation. This segmentation allows for simplified trimming procedures compared to trimming multiple simultaneously-active branches.
Solution Approach 2:
The patent performs preliminary trimming of each detection circuit during the manufacturing process before final assembly. By pre-trimming each circuit segment independently, the system reduces the complexity and time required for final system-level trimming and testing.
3Adaptability or versatility
If conventional temperature detectors are used with multiple branches, then detection coverage is improved, but device complexity increases
Solution Approach 1:
The patent makes a single detection branch universal by enabling it to perform multiple detection functions across different temperature ranges. Through dynamic switching and sequential activation, one branch structure serves the role of multiple branches would traditionally play, reducing overall device complexity while maintaining comprehensive detection coverage.
Solution Approach 2:
The patent adds the time dimension to temperature detection by sequentially activating different detection circuits at different temperature ranges. This temporal dimension allows the system to achieve multi-point detection coverage without requiring spatial multiplication through multiple parallel branches, thereby simplifying the device structure.
Data Source
AI summary
Temperature detectors include a temperature sensor that is configured to generate temperature tracking signals that indicate that a detected temperature is above, below or in a temperature range that corresponds to a selected one of a series of temperature control signals that indicate a series of temperature ranges. A control circuit is configured to sequentially supply the selected one of the series of control signals to the temperature sensor in response to the temperature tracking signals. The series of temperature control signals may indicate a series of overlapping temperature ranges, such that the temperature detector has a hysteresis characteristic. Analogous methods also may be provided.