Thermal Model Estimates Ambient Temperature for Computing System
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Solution Overview
Problem
Handheld wireless communications devices face thermal management challenges due to high power consumption and limited cooling capacity, leading to potential overheating issues, especially in varying ambient temperatures, where it is difficult to accurately measure ambient temperature for effective thermal control.
Innovation Solution
A method using a 'perturbed' temperature model that estimates target location temperatures without direct ambient temperature measurement, by incorporating ambient temperature information into the thermal management system during manufacturing, allowing the device to adjust power consumption limits based on estimated temperatures to maintain thermal constraints, even in different ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is placed at a cold spot to measure ambient temperature, then ambient temperature information can be obtained, but the sensor will be affected by internal heat generation and cannot accurately represent true ambient temperature
Solution Approach 1:
The patent uses a thermal model as an intermediary to estimate ambient temperature. Instead of directly measuring ambient temperature with a sensor that would be contaminated by internal heat, the system uses a thermal model that processes readings from internal sensors (located in components like CPU, battery, RF amplifier) to calculate and estimate the ambient temperature. This intermediary approach filters out the harmful internal heat interference while preserving the useful ambient temperature information.
2Reliability
If multiple temperature sensors are placed throughout the system to monitor all critical points, then thermal management accuracy is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the function of direct ambient temperature measurement from the physical sensor placement problem. Instead of placing sensors at every critical point or using a dedicated ambient temperature sensor, the system extracts ambient temperature information by processing data from existing internal temperature sensors through a thermal model. This removes the need for additional sensors while maintaining thermal management accuracy.
Solution Approach 2:
The patent creates a virtual copy of the ambient temperature measurement function through mathematical modeling. Rather than physically placing a sensor to directly measure ambient temperature, the system uses a thermal model that copies the measurement function by calculating estimated ambient temperature from internal sensor readings, thereby achieving the same information goal without the physical complexity.
3Productivity
If the system allows higher operating temperatures to maintain performance in hot weather, then user performance is preserved, but the risk of overheating and thermal issues increases
Solution Approach 1:
The patent implements dynamic thermal management by continuously adjusting power consumption limits based on real-time temperature conditions. The system dynamically modifies operating parameters such as CPU frequency, RF power amplifier output, and display brightness according to the estimated ambient temperature and internal component temperatures. This dynamic adjustment allows the system to maintain high performance when temperatures are acceptable while preventing overheating when temperature limits are approached, optimizing the balance between productivity and thermal safety.
Data Source
AI summary
A computing system has a thermal manager that changes a power consuming activity limit in the device based on an estimate of temperature of a target location in the system. There are several temperature sensors that are not at the target location. An estimator computes the target location temperature estimate using a thermal model and, as input to the thermal model, data from the sensors. The thermal model produces different estimates of the target location temperature at different ambient temperatures but without computing or measuring the ambient temperatures. Other embodiments are also described and claimed.