Non-Linear Converter Circuit for Linear Diode Temperature Output
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Solution Overview
Problem
Accurate temperature measurement on integrated circuits using diode voltages is challenging due to the non-linear temperature behavior of diodes, which requires effective linearization of non-linear responses.
Innovation Solution
A non-linear converter system comprising a non-linear voltage divider, analog multiplexer, and comparator, along with digital potentiometers for calibration, to convert non-linear voltage responses into linearized digital outputs, and extend the resolution of digital-to-analog converters by adjusting resistor configurations and using precision voltage references.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If diode voltages are used for temperature measurement, then temperature sensing capability is provided, but measurement precision deteriorates due to non-linear temperature behavior of diodes
Solution Approach 1:
The patent segments the non-linear temperature response into multiple linear regions by using a lookup table that stores pre-calculated linearization data for different temperature ranges. The system divides the overall temperature measurement range into discrete segments, each with its own linearization characteristics, thereby improving measurement precision across the full range while managing the non-linearity issue.
Solution Approach 2:
The patent changes the parameter representation by converting the non-linear diode voltage response into a linearized temperature scale through mathematical transformation. A lookup table stores pre-computed linearization factors that transform the non-linear voltage readings into linear temperature values, effectively changing the output parameter from non-linear to linear while maintaining measurement capability.
2Measurement precision
If non-linear voltage divider with multiple resistors is used, then linearization capability is improved, but device complexity increases
Solution Approach 1:
The patent uses a lookup table that copies pre-calculated linearization data into the device, avoiding the need for complex real-time computational circuits. Instead of implementing sophisticated analog linearization circuits with many resistors, the system copies stored linearization characteristics from the lookup table into register files, thereby achieving high linearization accuracy with simpler hardware.
Solution Approach 2:
The patent performs preliminary linearization calculations during device fabrication or initialization, storing the results in a lookup table before the device is put into service. This preliminary action eliminates the need for complex real-time linearization circuits, as the linearization data is pre-computed and stored, reducing device complexity while maintaining measurement precision.
3Measurement precision
If lookup table with linearization data is implemented, then measurement precision is improved, but loss of time occurs during linearization conversion
Solution Approach 1:
The patent segments the lookup table into multiple smaller register files, each storing linearization data for a specific temperature range. This segmentation allows the system to search only within the relevant temperature range segment rather than the entire lookup table, significantly reducing the time required to find the appropriate linearization data while maintaining measurement precision.
Solution Approach 2:
The patent performs preliminary organization of the lookup table data during device initialization, sorting and indexing the linearization data by temperature ranges. This preliminary action enables rapid retrieval during operation by allowing the system to directly access the appropriate temperature range segment without scanning the entire lookup table, thereby reducing conversion time while maintaining accuracy.
4Ease of operation
If digital potentiometers are used for calibration, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical potentiometers with digital potentiometers that are controlled by digital signals. This substitution eliminates the need for physical adjustment mechanisms while providing programmable control, thereby improving ease of operation through software-based calibration while the increase in device complexity is offset by the elimination of mechanical components.
Solution Approach 2:
The patent integrates the digital potentiometers into the existing ADC and comparator circuitry, allowing the same components to serve multiple functions: normal signal conversion and calibration adjustment. This multi-functionality approach enables calibration capability without adding completely separate dedicated components, thereby improving ease of operation while minimizing the increase in device complexity.
Data Source
AI summary
A non-linear converter comprising a non-linear voltage divider having a plurality of resistors representing a non-linear transfer function, an analog multiplexer having analog multiplexer inputs coupled to the non-linear voltage divider and configured to output an analog multiplexer output, the analog multiplexer chooses one of the plurality of resistors based on a logic signal and the non-linear transfer function, an analog comparator having an analog comparator first input configured to receive an analog input voltage, an analog comparator second input configured to receive the analog multiplexer output and the analog comparator configured to output a comparator voltage output and a logic loop coupled to the analog comparator and configured to receive the comparator voltage output and configured to output the logic signal, wherein the logic signal represents a linearized digital word.