On-Chip Temperature Sensor Calibration via Variable Substrate Heating
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Solution Overview
Problem
The calibration of on-chip temperature sensors in integrated circuits is costly and time-consuming due to the need for precise external temperature control and multiple calibration points, with existing methods struggling to achieve the required accuracy of ±0.1° C.
Innovation Solution
A temperature sensing circuit integrated on a semiconductor substrate with a substrate heating circuit that allows for variable temperature control, using a digital control circuit to heat the substrate to different temperatures and an ADC to convert base-to-emitter voltage to digital signals, enabling calibration without external temperature input by performing numerical curve fitting to estimate temperature coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external temperature control equipment is used for calibration, then temperature measurement accuracy can be achieved, but production cost and calibration time increase significantly
Solution Approach 1:
The patent extracts the temperature control function from external equipment and integrates it directly into the semiconductor substrate through an on-chip heating circuit. This allows the temperature sensor and heating element to be co-located, eliminating the need for external temperature control equipment and significantly reducing calibration time while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces a digital control circuit as an intermediary that manages the heating process and coordinates with the temperature sensor. This intermediary controls the heating circuit to provide precise temperature steps, enabling accurate calibration without requiring external temperature control equipment.
2Measurement precision
If external temperature control equipment is used for calibration, then temperature measurement accuracy can be achieved, but production cost increases
Solution Approach 1:
The patent merges the temperature sensor, heating circuit, and control logic into a single integrated circuit chip. By combining these previously separate components into one unit, the patent eliminates the need for external temperature control equipment, simplifies the manufacturing process, and reduces production costs while maintaining calibration accuracy.
Solution Approach 2:
The patent enables the temperature sensor to perform its own calibration by providing an on-chip heating circuit that can independently control the temperature environment. This self-service capability eliminates the need for external calibration equipment and reduces production costs associated with maintaining separate temperature control systems.
3Measurement precision
If multiple calibration points are used, then temperature coefficient accuracy improves, but calibration process complexity and time increase
Solution Approach 1:
The patent uses a dynamic heating approach where the heating circuit can rapidly adjust temperature in controlled steps. This dynamic temperature control allows the system to efficiently traverse multiple calibration points in a systematic manner, improving temperature coefficient accuracy while managing calibration process complexity through automated control.
Solution Approach 2:
The patent implements a feedback mechanism where the digital control circuit monitors temperature sensor output and adjusts heating accordingly to achieve precise temperature steps. This feedback control enables accurate collection of data at multiple calibration points while automating the process to reduce complexity.
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 calibration of temperature sensors within the integrated circuit, reducing production costs and time by eliminating the need for external temperature stabilization and achieving high accuracy in temperature coefficient estimation.
Implementation Method 1
a substrate heating circuit configured to heat said portion of semiconductor substrate in response to a temperature control signal
Implementation Method 2
a first bipolar transistor configured as a diode-connected device and biased by said first current to exhibit a first base-to-emitter voltage (Vbe)
Data Source
AI summary
A localized substrate heater is configured to apply variable substrate heating to an integrated bipolar transistor. The base-to-emitter voltage (Vbe) of that bipolar transistor at varying substrate temperature settings is sensed, with the sensed Vbe processed to determine temperature coefficients of the bipolar transistor. The bipolar transistor may, for example, be a circuit component of an integrated temperature sensing circuit.