BJT Temperature Detection Circuitry With Calibration-Free Sensing
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Solution Overview
Problem
Conventional temperature detection circuits in integrated circuits (ICs) consume significant silicon area and require part-to-part calibration at multiple temperatures to achieve accuracy, which is costly and time-consuming, especially when numerous detectors are needed to monitor various die locations for redundancy.
Innovation Solution
The proposed temperature detection circuitry uses a compact bipolar junction transistor (BJT) arrangement with self-biasing capabilities and a programmable resistor divider, allowing for accurate temperature detection without calibration, utilizing a single-temperature calibration and minimizing sensitivity to error sources like BJT base current effects and MOSFET mismatch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature detection circuits are used to achieve accurate temperature detection, then measurement precision is improved, but area of stationary object increases and manufacturing cost increases due to calibration requirements
Solution Approach 1:
The temperature detection function is segmented into two distinct circuits: a first temperature detection circuit using a first BJT with high area consumption but high accuracy, and a second temperature detection circuit using a second BJT with low area consumption but lower accuracy. The system selectively activates the first circuit only when high precision is required, otherwise using the compact second circuit, thus resolving the area-precision contradiction through functional segmentation.
Solution Approach 2:
The system dynamically switches between two temperature detection circuits based on operational requirements. A determination circuit identifies whether high-precision detection is needed, and accordingly enables either the first BJT-based circuit or the second BJT-based circuit. This dynamic adaptation allows the system to optimize between area usage and measurement precision in real-time.
2Measurement precision
If conventional temperature detection circuits are used to achieve accurate temperature detection, then measurement precision is improved, but loss of time increases due to part-to-part calibration requirements
Solution Approach 1:
The temperature detection functionality is divided into two circuits with different calibration requirements. The first BJT-based circuit requires full part-to-part calibration for maximum accuracy, while the second BJT-based circuit is designed to operate without such calibration. The determination circuit selects which circuit to use based on whether calibration time is available and high precision is needed, thus resolving the time-precision contradiction.
Solution Approach 2:
The system performs calibration in advance during manufacturing for the first BJT-based circuit, storing calibration data for later use. This preliminary calibration action allows the calibrated circuit to provide high precision measurements without requiring calibration time during operation, while the second circuit provides immediate uncalibrated detection capability.
3Measurement precision
If conventional temperature detection circuits are used to achieve accurate temperature detection, then measurement precision is improved, but device complexity increases due to calibration procedures
Solution Approach 1:
The temperature detection system is segmented into two circuits with different complexity levels. The first BJT-based circuit includes calibration components and procedures for high precision, while the second BJT-based circuit is simplified and calibration-free. The determination circuit and control logic manage which circuit operates, reducing overall system complexity by providing a simple alternative path when high precision is not required.
Solution Approach 2:
The calibration procedure and associated complexity are extracted from the main operational path. The second BJT-based circuit provides temperature detection functionality without requiring calibration procedures, removing the complexity burden from the primary operational flow. Calibration is isolated to the first circuit as an optional enhancement rather than a mandatory requirement for all operations.
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 solution achieves accurate temperature detection with low area usage, reducing costs and testing time, while maintaining precision across a defined operational temperature range without the need for extensive calibration, even when monitoring multiple die locations.
Implementation Method 1
accurate temperature detection circuitry that utilizes a compact circuit arrangement with bipolar junction transistors (BJTs) to accurately detect when a substrate temperature crosses a threshold temperature
Data Source
AI summary
An embodiment for an integrated circuit for temperature detection includes: a closed loop circuit branch including: a first bipolar junction transistor (BJT), a first resistor coupled between a first base of the first BJT and a junction node, and an amplifier having an output coupled to the junction node and a non-inverting input coupled to a collector of the first BJT; and an open loop circuit branch including: a second BJT, a second resistor coupled between a base of the second BJT and the junction node, a third resistor coupled between the base of the second BJT and ground, and a comparator having an inverting input coupled to a collector of the second BJT and an output configured to provide a digital voltage signal that corresponds to a temperature reading.