Distributed PTAT Temperature Sensing With Shared Bus Routing
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Solution Overview
Problem
Existing temperature sensing technologies in semiconductor dies face challenges in accurately measuring local temperatures due to thermal non-uniformities, requiring large and complex control circuits, and lack flexibility and efficiency in sensor placement and routing, leading to increased design complexity and cost.
Innovation Solution
An integrated circuit with a PTAT controller and distributed temperature sensors uses an addressable bus for routing, common-centroid arrays, and Kelvin sensing to reduce complexity and allow flexible sensor placement, minimizing congestion and enabling efficient temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple temperature sensors are distributed across the semiconductor die to measure local temperatures, then measurement precision is improved, but device complexity increases due to multiple control circuits
Solution Approach 1:
Multiple temperature sensors share a single PTAT controller that is multiplexed to control all sensors. The controller is shared across multiple sensors through time-division multiplexing, allowing one controller to manage N sensors sequentially. This merging approach maintains accurate temperature measurements at multiple locations while significantly reducing the number of control circuits required.
Solution Approach 2:
The PTAT controller is designed as a universal control unit that can manage multiple temperature sensors through multiplexing. The same controller hardware performs the function of controlling multiple sensors at different locations, making the control circuit multi-functional rather than dedicated to a single sensor. This universality reduces overall system complexity while maintaining measurement capabilities.
2Measurement precision
If sensors are placed close to the components being monitored to accurately reflect actual temperature, then measurement precision is improved, but routing complexity and congestion increase
Solution Approach 1:
Multiple sensors located at different positions on the die share common routing paths to the single PTAT controller. By consolidating the control architecture to a single controller, the patent reduces the number of independent routing paths needed, thereby minimizing routing congestion while still allowing sensors to be placed close to monitored components for accurate local temperature measurement.
3Ease of manufacture
If identical sense devices are used at multiple locations to simplify design, then ease of manufacture is improved, but adaptability to different temperature conditions decreases
Solution Approach 1:
While identical sense device structures are used throughout (maintaining ease of manufacture), each sensor measures the local temperature at its specific location on the die. The system accepts and processes temperature readings from multiple locations, allowing the identical devices to adapt to different local thermal conditions through their spatial distribution rather than through device differentiation.
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 simplifies design, reduces manufacturing costs, and enhances flexibility in sensor placement and number, while maintaining accurate temperature measurements by minimizing interference and congestion.
Implementation Method 1
Semiconductor temperature sensors are often based on a proportional-to-absolute-temperature (PTAT) technique. The PTAT technique uses the exponential dependence on temperature and voltage of a current-voltage characteristic of a semiconductor junction, such as in a diode or in a similar device, e.g., a bipolar junction transistor or a subthreshold field effect transistor.
Implementation Method 2
By measuring the voltage difference for such a semiconductor junction at two different current densities, the temperature can be determined. Notably, if the two current densities have a ratio of M, then the difference in semiconductor-junction voltage may be expressed as an equation involving Boltzmann's constant, absolute temperature, and electron charge.
Implementation Method 3
sense devices 110-1 and 110-2 through 110-10 may be implemented by tiling nine approximately identical sense devices in a 3-by-3 grid 210-1. The central site in this tiling may be used to implement sense device 110-1, while the remaining eight outer sites are electrically coupled in parallel to implement sense device 110-2 in FIG. 1. Using this spatial configuration, the effect of temperature gradients across the sense area can be reduced
Implementation Method 4
signal lines for analog signals in the addressable bus are reused when communicating between the controller and different temperature sensors
Data Source
AI summary
An integrated circuit that controls distributed temperature sensors in a semiconductor die is described. This integrated circuit may include: memory; a controller (such as a PTAT controller) coupled to the memory; temperature sensors distributed at measurement locations in the semiconductor die (such as remote locations from the controller), where a given temperature sensor includes building blocks (or components) that are common to the temperature sensors; and routing between the controller and the building blocks over an addressable bus, where signal lines for analog signals in the addressable bus are reused when communicating between the controller and different temperature sensors.