Multi-Sampled Charge-Sharing Thermometer for Low-Noise Memory Sensing
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Solution Overview
Problem
Memory devices face performance penalties due to the need for thermometers to determine and provide temperature values, which can be inaccurate during noisy operations, affecting the performance-enhancing techniques in memory devices.
Innovation Solution
A multi-sampled, charge-sharing thermometer that averages temperature conversions over thousands of phases to reduce noise and systematic errors, using a diode with a threshold voltage that changes with temperature, an analog-to-digital converter, and counters to generate accurate digital temperature codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the thermometer provides temperature values continuously in the background, then the temperature information is always current and available, but conversion errors occur due to noisy phases of operation
Solution Approach 1:
The thermometer operates in periodic cycles, alternating between measurement phases and noisy operation phases. By scheduling temperature conversions during specific periodic windows when noise is minimized, the system maintains current temperature information while avoiding conversion errors during noisy phases.
Solution Approach 2:
The system monitors the quality of temperature conversions and uses feedback mechanisms to detect when conversions occur during noisy phases. Based on this feedback, the thermometer can retry conversions or adjust timing to ensure accurate temperature readings are provided to the controller.
2Measurement precision
If the thermometer determines and provides temperature values on request, then conversion errors are avoided, but performance penalties occur due to waiting time
Solution Approach 1:
The thermometer performs temperature conversions in advance during quiet phases before the controller needs the data. By preparing temperature information proactively during periods when noise is minimal, the system ensures accurate readings are ready and available when requested, eliminating waiting time and maintaining high productivity.
Solution Approach 2:
The thermometer continuously performs temperature measurements in the background during appropriate phases, maintaining an up-to-date temperature value without interrupting memory operations. This continuous background operation eliminates the need for the controller to wait, thereby maintaining productivity while ensuring accuracy.
3Device complexity
If traditional thermometer methods are used, then device complexity is low, but temperature readings are inaccurate during noisy operations
Solution Approach 1:
The thermometer implements dynamic timing control that adapts its operation based on the noise conditions in the memory device. By dynamically adjusting when measurements are taken and how conversions are performed, the system achieves high accuracy without requiring complex additional hardware, maintaining simplicity while improving precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides continuous and accurate temperature values, reducing noise and systematic errors, thereby enhancing the performance of memory devices by ensuring up-to-date and reliable temperature information.
Implementation Method 1
a diode having a threshold voltage that changes with temperature
Implementation Method 2
the first capacitor to connect to the second capacitor and equalize charge between the first capacitor and the second capacitor
Data Source
AI summary
A memory device includes an array of memory cells, a diode having a threshold voltage that changes with temperature, an analog-to-digital converter (ADC), and a pulse generator. The ADC includes a voltage comparator having a positive terminal coupled with the diode. The ADC further includes a first capacitor coupled between a negative terminal of the voltage comparator and ground, and a second capacitor selectively coupled between the first capacitor and a voltage reference node. The second capacitor has a smaller capacitance than that of the first capacitor. The pulse generator is coupled with the ADC and generates pulses. The pulses cause the first capacitor to connect to the second capacitor and equalize charge between the first capacitor and the second capacitor. An inverted signal of the pulses causes the second capacitor to be coupled with the voltage reference node to pre-charge the first capacitor.