Semiconductor Refresh Signal Period Control
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Solution Overview
Problem
Semiconductor devices face challenges in maintaining operational reliability due to varying operation speeds with temperature changes, which can lead to malfunctions, and require periodic refresh signals for volatile memory devices like DRAM to prevent data loss.
Innovation Solution
A semiconductor device incorporating a temperature code latch circuit and a period selection circuit that generates a refresh signal with varying periods based on internal temperature, using gradient selection signals to control the period variation rate across different temperature sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the operation speed of the semiconductor device is increased to improve productivity, then the device can perform operations faster, but the reliability deteriorates due to temperature-induced speed variations causing malfunctions
Solution Approach 1:
The patent applies dynamics by making the refresh signal period adjustable rather than fixed. The period selection circuit dynamically changes the refresh period based on temperature conditions, allowing the system to adapt to temperature-induced speed variations and maintain both productivity and reliability across different operating conditions.
Solution Approach 2:
The patent changes the parameter of refresh signal period based on temperature conditions. By varying the period length according to temperature, the system compensates for temperature-induced operation speed changes, ensuring reliable operation while maintaining high productivity across the operating temperature range.
2Device complexity
If a fixed refresh signal period is used to simplify the device structure, then the device complexity is reduced, but the reliability deteriorates because the fixed period cannot adapt to temperature changes causing data loss
Solution Approach 1:
The patent segments the temperature range into multiple sections with different refresh periods. The period selection circuit divides the temperature operating range and selects appropriate refresh periods for different temperature sections, providing reliable data retention while managing complexity through structured segmentation rather than a single fixed period.
Solution Approach 2:
The patent introduces dynamic adjustment capability to the refresh signal period. Rather than using a fixed period, the system dynamically selects the appropriate period based on detected temperature conditions, ensuring reliability across varying temperatures while keeping the control mechanism manageable through the period selection circuit.
3Productivity
If the refresh signal period is extended to reduce the number of refresh operations, then the productivity is improved by reducing refresh overhead, but the reliability deteriorates due to increased risk of data loss in volatile memory
Solution Approach 1:
The patent changes the refresh period parameter based on temperature conditions. At higher temperatures where data retention is more challenging, the system uses shorter periods to maintain reliability. At lower temperatures, longer periods can be used to reduce refresh overhead, optimizing the balance between productivity and reliability across different thermal conditions.
Data Source
AI summary
A semiconductor device includes a temperature code latch circuit and a period selection circuit. The temperature code latch circuit latches a count code having a logic level combination corresponding to an internal temperature to output the latched count code as a temperature code. The period selection circuit selects a period of a refresh signal in response to the temperature code. A period variation rate of the refresh signal according to variation of the internal temperature is controlled by a first gradient selection signal in a first temperature section and is controlled by a second gradient selection signal in a second temperature section.