Dual-Current Digital Temperature Sensing for Nonlinear Error Correction
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Solution Overview
Problem
Semiconductor devices face performance degradation due to low temperature measurement accuracy, which affects their temperature sensitivity.
Innovation Solution
A digital temperature sensor that generates proportional to absolute temperature (PTAT) and complementary to absolute temperature (CTAT) currents, using oscillation circuits to produce clock signals with varying cyclic periods, and a conversion circuit to generate temperature codes that are corrected by calculating the difference between these codes, thereby compensating for nonlinear errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature measurement methods are used, then the measurement process is simple, but the temperature measurement accuracy is low
Solution Approach 1:
The temperature measurement is segmented into two separate measurement processes: one using PTAT current and another using CTAT current. Each measurement path is processed independently through oscillation circuits and conversion circuits, allowing the system to combine results for higher accuracy while maintaining manageable complexity in each individual path.
Solution Approach 2:
The patent uses a composite measurement approach by combining PTAT (proportional to absolute temperature) and CTAT (complementary to absolute temperature) current measurements. This composite method leverages the complementary characteristics of both current types to achieve higher temperature measurement accuracy than either method alone.
2Measurement precision
If PTAT current measurement is used, then temperature proportionality is achieved, but nonlinear errors occur
Solution Approach 1:
The system implements a feedback mechanism where the temperature codes from both PTAT and CTAT measurements are fed into a calculation circuit. This circuit processes both measurements and generates a corrected temperature code that compensates for nonlinear errors, ensuring reliable and linear temperature representation.
Solution Approach 2:
The patent applies counterweight by using CTAT measurement to compensate for the nonlinear errors inherent in PTAT measurement. The calculation circuit computes a corrected temperature code by combining both measurements, effectively using the CTAT path as a counterbalance to eliminate systematic errors in the PTAT path.
3Productivity
If temperature compensation is performed, then semiconductor device performance is improved, but measurement accuracy requirements increase
Solution Approach 1:
The patent changes the measurement parameters by using dual current types (PTAT and CTAT) with different temperature dependencies. This parameter diversification allows the system to achieve high measurement accuracy through mathematical combination of the two measurements, enabling effective temperature compensation for semiconductor device performance optimization.
Data Source
AI summary
A digital temperature sensor includes a current generation circuit, an oscillation circuit, a conversion circuit and a calculation circuit. The current generation circuit generates a proportional to absolute temperature (PTAT) current and a complementary to absolute temperature (CTAT) current. The oscillation circuit generates a first clock signal having a first cyclic period based on the PTAT current and generates a second clock signal having a second cyclic period based on the CTAT current. The conversion circuit generates a first temperature code based on the first clock signal such that the first temperature code decreases as the operation temperature increases and generates a second temperature code based on the second clock signal such that the second temperature code increases as the operation temperature increases. The calculation circuit calculates a difference between the first temperature code and the second temperature code and generates a corrected temperature code based on the difference.