High Accuracy Temperature Sensor Using Band-Gap and Sigma-Delta ADC
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Solution Overview
Problem
Temperature sensors in semiconductor devices face challenges in achieving high accuracy due to temperature variations, particularly in NAND flash memory devices, where read errors and threshold voltage distributions are affected, necessitating effective trimming methods to compensate for these changes.
Innovation Solution
A temperature sensor design utilizing a precision band-gap circuit and a sigma delta modulator (SDM) analog-to-digital converter (ADC) with a proportional to absolute temperature (PTAT) circuit, which allows for single-temperature trimming and provides a digital output with precise temperature calculations, enabling accurate temperature measurement across a wide range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional temperature sensors are used in semiconductor devices, then temperature measurement is possible, but measurement precision deteriorates due to temperature variations affecting transistor parameters
Solution Approach 1:
The patent replaces traditional mechanical trimming methods with electrical trimming through voltage adjustments. The bandgap reference circuit and PTAT circuit use voltage control to compensate for temperature variations, eliminating the need for physical mechanical adjustments and improving both measurement precision and reliability across temperature ranges.
Solution Approach 2:
The patent changes the operating parameters of the temperature sensor by adjusting voltage levels and circuit configuration based on temperature conditions. The bandgap reference voltage and PTAT voltage are dynamically adjusted to maintain accurate temperature measurements despite variations in transistor parameters caused by temperature changes.
2Measurement precision
If high accuracy temperature measurement is achieved through trimming, then measurement precision improves, but device complexity increases due to additional trimming circuits
Solution Approach 1:
The patent merges the trimming functionality into the existing bandgap reference circuit and PTAT circuit. The same circuitry that generates reference voltages also performs the trimming function through voltage adjustments, eliminating the need for separate trimming circuits and reducing overall device complexity while maintaining high measurement precision.
Solution Approach 2:
The bandgap reference circuit and PTAT circuit are designed to serve multiple functions: generating reference voltages, compensating for temperature variations, and performing trimming operations. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity while achieving high measurement accuracy.
3Adaptability or versatility
If multiple resolution settings are provided, then adaptability improves for various applications, but device complexity increases due to additional circuit configurations
Solution Approach 1:
The patent implements dynamic resolution switching that allows the temperature sensor to adapt its output resolution based on application requirements. The circuit can dynamically adjust between different resolution levels (e.g., 8-bit, 10-bit, 12-bit) through software control or simple configuration bits, providing high adaptability without requiring multiple separate hardware circuits for each resolution level.
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
This solution enhances the accuracy and cost-effectiveness of temperature measurement by reducing the need for expensive external test setups and allows for multiple resolution settings based on the same ADC output, catering to various application requirements.
Implementation Method 1
A temperature sensor design utilizing a precision band-gap circuit
Implementation Method 2
a sigma delta modulator (SDM) analog-to-digital converter (ADC) with a proportional to absolute temperature (PTAT) circuit
Data Source
AI summary
A temperature sensor is disclosed. In one aspect, the temperature sensor provides a digital output having a precise degree/code step. For example, each step in the digital output code may correspond to one degree Celsius. In one aspect, a temperature sensor comprises a precision band-gap circuit and a sigma delta modulator (SDM) analog-to-digital convertor (ADC). A bandgap voltage and a PTAT voltage may be provided from the band-gap circuit as an input to the SDM ADC. The SDM ADC may produce an output based on the difference between the PTAT voltage and the bandgap voltage. The temperature sensor may also have logic that outputs a temperature code based on the output of the SDM ADC.