BJT Temperature Sensor Circuit Using Dual-Current Voltage Sampling
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Solution Overview
Problem
Existing temperature sensors, particularly those using bipolar junction transistors (BJTs), require reference circuits or reference voltages for calibration, which increases manufacturing costs and may lead to signal loss and reduced accuracy.
Innovation Solution
A temperature sensor circuit that utilizes a diode-connected BJT to generate emitter-base voltage differences without additional reference circuits, calculating temperature information by comparing emitter-base voltages using controlled collector currents, and converting the result into digital form using analog-to-digital converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference circuits or reference voltages are used for calibration in temperature sensors, then manufacturing accuracy and temperature measurement precision are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the reference circuit component from the temperature sensor system. By using the bandgap voltage generator to provide a temperature-compensated reference voltage internally, the need for external reference circuits is removed, thereby reducing device complexity while maintaining measurement precision through the inherent temperature compensation mechanism of the bandgap circuit
Solution Approach 2:
The bandgap voltage generator serves multiple functions: it provides a stable reference voltage for the temperature measurement circuit and simultaneously compensates for temperature variations. This multi-functionality eliminates the need for separate reference circuits, reducing overall device complexity while maintaining accurate temperature measurement
2Measurement precision
If reference circuits are added for calibration, then temperature sensing accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent removes the requirement for external reference circuits by integrating temperature compensation functionality into the bandgap voltage generator. This extraction of the reference circuit requirement simplifies the manufacturing process and reduces component costs while maintaining accurate temperature sensing through the integrated compensation mechanism
Solution Approach 2:
The temperature sensor system performs self-calibration through the bandgap voltage generator's inherent temperature compensation capability. The circuit automatically compensates for temperature effects without requiring external reference components, thereby reducing manufacturing complexity and cost while maintaining sensing accuracy
3Measurement precision
If additional reference circuits are used, then calibration accuracy is improved, but signal integrity deteriorates due to potential signal loss
Solution Approach 1:
The patent merges the reference voltage generation and temperature compensation functions into a single bandgap voltage generator circuit. This integration eliminates multiple connection points and interfaces that could cause signal loss, thereby maintaining signal integrity while achieving accurate calibration through the unified circuit design
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
This approach allows for accurate temperature sensing with improved signal integrity, higher resolution, and reduced manufacturing costs by eliminating the need for reference circuits, while maintaining better linearity and resolution.
Implementation Method 1
a first emitter-base voltage in response to the first collector current and a second emitter-base voltage in response to the second collector current are generated by the bipolar junction transistor, the first emitter-base voltage and the second emitter-base voltage respectively indicating temperature information
Data Source
AI summary
A temperature sensor circuit, a control circuit, and a control method are provided. The temperature sensor circuit comprises a temperature sensor and a control circuit. The control circuit is coupled to the temperature sensor and comprises a current source, a sampling circuit, and a computing circuit. The current source is configured to provide a first current and a second current to the temperature sensor in different time periods. The sampling circuit is coupled to the temperature sensor and configured to obtain and store a first voltage information and a second voltage information from the temperature sensor when the first current and second current are respectively provided. The computing circuit is coupled to the sampling circuit and configured to generate a sensing result corresponding to a difference of subtracting the second voltage information from the first voltage information.