NAND Die Temperature Sensor Fault Isolation
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Solution Overview
Problem
Defective temperature sensors on dies within non-volatile storage devices can lead to incorrect thermal calculations, resulting in unnecessary throttling or shutdown of the storage device, and causing yield loss during manufacturing.
Innovation Solution
A storage device identifies dies with defective temperature sensors by executing a defective temperature sensor scheme, which compares the temperature of each die against benchmarks, determines temperature variances, and excludes faulty temperature readings from thermal calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the controller uses temperature readings from dies with defective temperature sensors in thermal calculations, then the storage device can operate with all dies included, but the controller may calculate incorrect temperature leading to unnecessary thermal throttling or shutdown
Solution Approach 1:
The patent extracts and removes defective temperature sensor readings from the thermal calculation process. The controller identifies dies with defective temperature sensors and excludes their temperature readings from composite temperature calculations, thereby preventing incorrect thermal management decisions while maintaining operation continuity with remaining healthy dies
Solution Approach 2:
The patent performs preliminary identification of defective temperature sensors before incorporating temperature readings into thermal calculations. The controller screens temperature sensor readings in advance and marks defective sensors for exclusion, ensuring that only valid temperature data is used in subsequent thermal management decisions
2Measurement precision
If the storage device is discarded during manufacturing when composite temperature exceeds threshold, then defective temperature sensors can be detected, but yield loss occurs due to false positives from defective sensors
Solution Approach 1:
The patent implements feedback mechanisms during manufacturing testing where the controller monitors temperature sensor readings and provides feedback on their validity. When a temperature sensor is identified as defective, the controller adjusts the testing process to account for the defective reading, preventing false positive rejections and reducing yield loss while maintaining accurate temperature threshold detection
Solution Approach 2:
The patent introduces an intermediary validation process between temperature sensor readings and final composite temperature calculations. The controller acts as an intermediary that screens and validates individual die temperature readings before incorporating them into the overall thermal assessment, filtering out false positives from defective sensors
3Reliability
If the controller monitors thermal states of all components including dies with defective temperature sensors, then comprehensive thermal monitoring is achieved, but incorrect temperature calculations result in extreme thermal throttling states
Solution Approach 1:
The patent removes defective temperature sensor data from thermal management operations. The controller identifies and excludes readings from dies with defective temperature sensors, thereby maintaining comprehensive thermal monitoring coverage through remaining healthy sensors while preventing defective data from triggering extreme throttling or shutdown operations
Data Source
AI summary
A storage device identifies a die with a defective temperature sensor and excludes the die temperature from thermal calculations. The storage device includes a memory device with multiple dies. Each die includes a temperature sensor. A controller on the storage device executes a defective temperature sensor scheme to obtain a temperature for a first die in the memory device. The controller compares the first die temperature against a benchmark. The controller determines that the first die includes a defective temperature sensor if there is a temperature variance in the first die temperature and the benchmark and if the temperature variance is greater than a die temperature variation threshold.