Distributed PTAT Temperature Sensing With Shared Analog Bus Routing
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Solution Overview
Problem
Existing integrated circuits with temperature sensors face challenges in accurately measuring temperature due to large and complex control circuits, difficulty in locating sensors close to the measurement location, and limited flexibility in adapting the number of sensors, leading to increased complexity and cost.
Innovation Solution
An integrated circuit with distributed temperature sensors that uses a PTAT controller, common-centroid array of sensor devices, and an addressable bus for routing analog signals, allowing flexible adaptation of sensor numbers and reducing routing congestion and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple temperature sensors are implemented with individual control circuits, then temperature measurement accuracy is improved, but device complexity and area increase
Solution Approach 1:
Multiple temperature sensors share a common control circuit and readout path. The control circuit generates PTAT currents that are distributed to multiple sensor devices, and the voltage differences from all sensors are read through a single shared path, eliminating the need for individual control circuits for each sensor.
Solution Approach 2:
The control circuit is designed to serve multiple temperature sensors simultaneously, performing the functions of current generation, switching, and voltage measurement for all sensors through a single multi-functional unit, rather than requiring dedicated circuits for each sensor.
2Measurement precision
If temperature sensors are located close to the measurement location, then measurement accuracy is improved, but routing complexity and congestion increase
Solution Approach 1:
The sensor array is divided into multiple independently addressable sensor devices that can be selectively activated. The control circuit uses segmented current paths and switching mechanisms to route currents to specific sensor groups or individual sensors, reducing routing congestion while maintaining close proximity to measurement locations.
3Adaptability or versatility
If the number of temperature sensors is increased to cover multiple locations, then measurement coverage is improved, but control circuit size and cost increase
Solution Approach 1:
The control circuit incorporates dynamic switching mechanisms that allow flexible configuration of which sensors are active and how they are connected to the readout path. This dynamic reconfigurability enables the same control circuit to support varying numbers of sensors and different measurement configurations without requiring additional circuitry.
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 simplifies the design and fabrication of the integrated circuit, reduces costs, and increases yield by allowing flexible sensor adaptation and efficient routing, enabling accurate temperature measurement with reduced complexity and increased design flexibility.
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 [equation showing voltage difference proportional to absolute temperature].
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.