Thermal Dissipation Techniques on Snapdragon Systems
As IoT devices become more capable, delivering the necessary performance to enable immersive experiences to users is a complex challenge owing to the power and thermal constraints on these devices. To address this challenge, a design approach that specifically caters to portable devices without a constant power source is essential. An optimal and thermal efficient design is only possible by taking a holistic approach to power management across the system including the choice of materials for the product enclosures. Qualcomm does an excellent job on the Snapdragon platforms’ power and thermal management by designing specialized processing engines, smartly integrating them, and optimizing the system software. The different processing engines are specifically designed to perform a given task or enable a user experience at optimal power and thermal levels. The Snapdragon platform includes the CPU, PMIC, graphics processing unit (GPU), digital signal processor (DSP), image signal processor (ISP), display engine, video engine, sensor engine, and many other specialized processing engines that are designed with optimized architecture for performance and power. The complete system architecture is custom designed by Qualcomm including interconnects, caches, memory systems, and more. This is critical for all these processing engines to work well together. The system software that run on these engines is optimized too to take advantage of power saving hardware features and to make intelligent power management decisions. Qualcomm’s thermal management algorithm provides a safety net, preventing the device from causing damage to components or injury/discomfort to users. To accomplish this, one must lower power dissipation to keep the temperature at acceptable levels. Let us dig deeper to see how this accomplished. The Thermal core is part of the upstream Linux solution for thermal management and it includes:
- Thermal zone: Provides a means to expose thermal sensors through the sysfs as well as define thermal configurations based off of the sensor.
- Cooling device: Modules that can be throttled to reduce temperature. The different cooling devices(not exhaustive) available and their actions are tabulated below:
- Thermal governor: A temperature monitor algorithm that controls the temperature of a thermal zone within a limit by mitigating the cooling devices associated with the zone.