Digital Temperature Sensor Correction With Reduced Analog Trim
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Solution Overview
Problem
Existing temperature sensor technologies face challenges such as mismatched capacitance, nonlinear errors, and accuracy issues due to operational amplifier limitations, leading to inadequate high-accuracy temperature sensing in various applications.
Innovation Solution
A circuit optimization method for digital domain correction involves subjecting negative and positive temperature coefficient voltages to switch timing control, integrating them into an operational transconductance amplifier, and using a switch sampling circuit to generate feedback through a comparator, with digital domain processing to achieve high-accuracy temperature sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a trim capacitor with small unit capacitance is used in the analog domain, then the capacitance ratio can be achieved, but the small capacitance per unit area results in significant mismatch and requires large layout area
Solution Approach 1:
The patent replaces the analog domain trim capacitor (mechanical/electrical component) with a digital domain capacitance ratio implementation. The capacitance ratio is achieved through digital processing of temperature signals rather than physical capacitor arrays, eliminating the need for large-area trim capacitors while maintaining measurement precision.
Solution Approach 2:
The patent introduces digital signal processing as an intermediary between the temperature sensing element and the output. Instead of directly using analog capacitors to achieve the desired ratio, the system uses digital algorithms to compute the temperature based on voltage signals, with the capacitance ratio effectively implemented in the digital domain through processing cycles.
2Ease of manufacture
If operational amplifier with limited gain is used, then the circuit can be implemented, but nonlinear errors and accuracy problems occur
Solution Approach 1:
The patent replaces the reliance on operational amplifier gain (analog component performance) with digital domain processing. The temperature measurement is computed digitally from voltage signals, eliminating the propagation of nonlinear errors from the operational amplifier while maintaining ease of circuit implementation.
Solution Approach 2:
The patent employs feedback mechanisms in the digital domain to correct and refine temperature measurements. The system uses feedback loops that process temperature data digitally, allowing for compensation of errors and improvement of accuracy without requiring high-gain operational amplifiers.
3Measurement precision
If analog domain trim circuits are used for high-accuracy temperature sensing, then measurement precision is improved, but device complexity and layout area increase
Solution Approach 1:
The patent substitutes complex analog trim circuits with digital domain processing. The capacitance ratio and temperature calculations are performed digitally rather than through analog component matching, significantly reducing device complexity while maintaining or improving measurement precision.
Solution Approach 2:
The patent creates a universal digital processing framework that can achieve high-accuracy temperature sensing without requiring specialized analog trim circuits. The digital implementation provides multi-functionality, handling temperature measurement, calibration, and correction through software/algorithms rather than dedicated hardware circuits.
Data Source
AI summary
A circuit optimization method and system for a digital domain correction of a temperature sensor is provided. The method includes: subjecting negative temperature coefficient voltages Vbep and Vben to a switch timing control, thereby generating a corresponding negative temperature coefficient voltage Vbep and positive temperature coefficient voltage Dvbe as inputs into an operational transconductance amplifier (OTA) that serves as a core circuit of a Sigam-Delt analog-to-digital converter (ADC); and generating, by a switch sampling circuit, Vintx by integrating; inputting the Vintx into a comparator (CMP) to acquire a final ADC output; and sending a feedback through a digital domain to an analog domain control switch logic. The circuit optimization method intelligently finds the optimal temperature factor of different processes through the digital domain correction, thereby acquiring the desired ratio value more accurately. Meanwhile, the circuit optimization method reduces the trim circuit to be implemented in the analog domain.