Current-Mode Temperature Digitizer for Precision With Less Complexity
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Solution Overview
Problem
Voltage bandgap temperature sensors require high precision and architectural complexity to measure temperature accurately, leading to high costs and complexity.
Innovation Solution
An electrical current-based temperature sensor and digitizer using a sensor core, current comparator, and processor to generate and compare electrical currents, achieving precision through a successive approximation algorithm and oversampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage bandgap temperature sensors are used to measure temperature, then temperature measurement capability is achieved, but measurement precision and device complexity increase due to the need for high gain side circuits
Solution Approach 1:
The patent replaces voltage-based measurement with current-based measurement. By using current-mode circuitry instead of voltage-mode circuitry, the system avoids the need for high gain amplifiers and complex signal conditioning circuits. The current directly reflects temperature through the PTAT relationship, enabling simpler architecture while maintaining high measurement precision.
Solution Approach 2:
The patent changes the measurement parameter from voltage to current. By measuring current instead of voltage, the system achieves temperature measurement without requiring complex voltage amplification and comparison circuits. This parameter change fundamentally simplifies the architectural complexity while preserving measurement precision.
2Measurement precision
If voltage bandgap temperature sensors are used, then temperature measurement is achieved, but cost increases due to high precision requirements
Solution Approach 1:
The patent substitutes voltage measurement with current measurement, eliminating the need for expensive high-precision voltage amplifiers and comparison circuits. Current-mode operation allows for simpler, lower-cost circuit implementation while achieving the same measurement precision, thereby reducing manufacturing cost.
Solution Approach 2:
The patent employs simpler current-mode circuit components that are less expensive than the voltage-mode components required by traditional bandgap sensors. By using readily available current sources, mirrors, and comparators, the system achieves high precision temperature measurement at lower cost.
3Loss of information
If voltage differences in millivolt range are used for temperature measurement, then temperature information can be obtained, but high gain side circuits are required increasing complexity
Solution Approach 1:
The patent replaces millivolt-range voltage measurement with current measurement. Current signals inherently provide better signal-to-noise ratio and do not require high gain amplification stages. The current-mode architecture directly converts temperature to measurable current without needing complex voltage amplification and signal conditioning circuits.
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
The solution provides accurate temperature measurement with reduced complexity and cost by processing signals in the current domain, reducing error sources and achieving high accuracy with an 11-bit digital output.
Implementation Method 1
The principle of such sensors is that the forward voltage of a silicon diode, which may be the base-emitter junction of a bipolar junction transistor (BJT), is temperature-dependent.
Implementation Method 2
a current comparator and a processor configured to perform multiple current comparisons using the sensor core, the digital to analog converter, and the current comparator
Data Source
AI summary
The described technology is generally directed towards an electrical current based temperature sensor and temperature information digitizer, referred to herein as a “temperature digitizer”. The temperature digitizer can include a sensor core, a digital to analog converter, a current comparator, and a processor. The processor can be configured to perform multiple current comparisons using the sensor core, digital to analog converter, and current comparator, and the processor can generate a digital code that reflects the results of the multiple current comparisons. The digital code represents the temperature.