Embedded BJT Thermal Sensor Layout for CPU Hot Spot Accuracy
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Solution Overview
Problem
Existing thermal sensors in integrated circuits face challenges in accurately measuring temperature due to deviations from ideal characteristics, which can lead to errors in temperature measurements and reduced performance and accuracy in calibration processes.
Innovation Solution
The proposed solution involves a thermal sensor circuit that utilizes a BJT pair with current sources and transistors connected in series, along with an amplifier and an adder to generate a reference voltage. This design includes standard cells to form BJT structures that can be directly embedded into a CPU design, allowing for precise temperature detection with reduced area penalty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal sensors are embedded closer to hot spots in CPU design, then temperature measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines the thermal sensor circuit with standard CPU design elements by integrating BJT structures that can be directly embedded into the CPU layout. The sensor shares physical space and structural elements with the CPU, merging temperature sensing functionality with the processing unit without requiring separate dedicated sensor modules.
Solution Approach 2:
The BJT structures serve dual purposes: they function as standard transistor components within the CPU circuitry while simultaneously acting as temperature sensing elements. This multi-functionality allows the same structural elements to contribute to both processing and thermal monitoring, reducing overall device complexity.
2Measurement precision
If BJT structures with different active region widths are used, then temperature measurement accuracy is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements BJTs with deliberately different active region widths at specific locations within the sensor circuit. This local variation in geometric quality creates distinct electrical characteristics that enhance temperature sensing capability. The different widths are strategically placed to generate measurable differences in voltage or current responses to temperature changes.
3Ease of manufacture
If standard cells are used to form BJT structures, then ease of manufacture is improved, but area of the device increases
Solution Approach 1:
The thermal sensor is constructed using multiple standard cell units that can be independently designed and then replicated or arranged in series. Each standard cell represents a modular segment containing essential BJT structures, allowing the overall sensor to be built from standardized building blocks that simplify manufacturing while enabling flexible area optimization.
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 enhances the accuracy of temperature measurements and improves thermal throttling of CPUs by embedding thermal sensors closer to hot spots, thereby preventing CPU degradation and optimizing power consumption.
Implementation Method 1
During operation, integrated circuits (ICs) generate heat that causes the temperature of the ICs to increase. As the temperature of the ICs increases, the performance and efficiency of the ICs may be impacted in various ways in response to variations of resistance and capacitance values of different materials within the ICs.
Data Source
AI summary
A semiconductor device includes a bipolar junction transistor (BJT) structure including emitters in a first well having a first conductive type, collectors in respective second wells, the second wells having a second conductive type different from the first conductive type and being spaced apart from each other with the first well therebetween, and bases in the first well and between the emitters and the collectors. The BJT structure includes active regions having different widths that form the emitters, the collectors, and the bases.