Portable Device Thermal Control Using Surface Temperature Limits

The patent replaces the conventional PCB temperature sensing approach with an optical measurement system. A camera captures thermal images of the device surface, and image processing algorithms extract actual surface temperature data. This optical substitution eliminates the distance-related measurement error between PCB and surface, enabling accurate real-time surface temperature monitoring without premature throttling.

The patent introduces a temperature calibration curve as an intermediary between the optical temperature measurement and the thermal management decision-making system. The calibration curve, established through controlled heating experiments, maps the relationship between surface temperature and internal component temperature. This intermediary enables accurate inference of internal temperatures from surface measurements, resolving the contradiction between surface temperature monitoring and internal thermal management.

The patent implements a closed-loop feedback system that continuously monitors actual surface temperature via optical measurement, compares it with the upper temperature limit, and dynamically adjusts the thermal throttling strategy. Instead of conservative pre-throttling, the system maintains full performance until surface temperature actually approaches the limit, then applies targeted throttling only when necessary. This feedback mechanism eliminates unnecessary performance reduction while ensuring temperature safety.

The patent transitions from static thermal management thresholds to dynamic, real-time temperature-based control. The thermal management parameters (such as power limits and throttling levels) are continuously adjusted based on the measured surface temperature and the calibrated relationship with internal component temperatures. This dynamic approach allows the system to maintain optimal performance across varying thermal conditions while preventing unsafe temperature excursions.