MOS Temperature Sensor Circuit Using Threshold Voltage Extraction
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Solution Overview
Problem
Conventional temperature sensing circuits in semiconductor devices rely on bipolar junction transistors (BJT), which require consideration of various skews, making precise temperature measurement challenging, especially in multi-chip packages where performance supplementation at specific temperatures is necessary.
Innovation Solution
A temperature sensor design that utilizes a reference voltage generator, a compare voltage generator, a temperature voltage generator based on a MOS transistor, and a comparator to measure temperature without BJTs, allowing for precise temperature sensing through amplified voltage comparison and control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a BJT-based temperature sensing circuit is used, then temperature sensing functionality is achieved, but measurement precision deteriorates due to various skews in BJT, CMOS, and resistor characteristics
Solution Approach 1:
The patent extracts and eliminates the BJT component from the temperature sensing circuit, replacing it with a MOS transistor-based implementation. This removal of the problematic BJT element directly addresses the measurement precision issue caused by BJT skews while maintaining the temperature sensing functionality through alternative MOS transistor characteristics.
Solution Approach 2:
The patent changes the fundamental parameter basis of temperature sensing from BJT voltage characteristics to MOS transistor threshold voltage characteristics. By utilizing the threshold voltage of MOS transistors which has different temperature dependence characteristics compared to BJT, the patent achieves more accurate temperature measurement without the skew problems associated with BJT, CMOS, and resistor variations.
2Reliability
If a BJT-based temperature sensing circuit is used, then temperature sensing is implemented, but circuit size increases
Solution Approach 1:
The patent removes the BJT component and associated biasing circuits from the temperature sensing implementation, replacing them with a more compact MOS transistor-based circuit. This extraction reduces the overall circuit area while maintaining reliable temperature sensing functionality.
3Measurement precision
If a BJT-based temperature sensing circuit is used, then temperature measurement is achieved, but operating current increases
Solution Approach 1:
The patent changes the operating principle from BJT-based voltage sensing to MOS transistor threshold voltage sensing. MOS transistors operate with lower current requirements compared to BJT circuits, especially when utilizing threshold voltage characteristics for temperature sensing. This parameter change enables precise temperature measurement with reduced operating current consumption.
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
Enables precise temperature measurement without BJTs, reducing circuit size and operating current, and maintaining miniaturization, while allowing for more precise temperature determination in semiconductor devices.
Implementation Method 1
a temperature voltage generator for generating a temperature voltage based on the reference voltage and a threshold voltage of a MOS transistor
Data Source
AI summary
A temperature sensor that can be used in semiconductor devices includes a reference voltage generator for dividing a power supply voltage and outputting a reference voltage, a compare voltage generator for outputting compare voltages with different levels depending on a change of a control signal, a temperature voltage generator for generating a temperature voltage based on the reference voltage and a threshold voltage of a MOS transistor, and a comparator for comparing an amplified temperature voltage and the compare voltage.