# Software thermal management
Source: [https://docs.qualcomm.com/doc/80-88500-4/topic/52_Software_thermal_management.html](https://docs.qualcomm.com/doc/80-88500-4/topic/52_Software_thermal_management.html)
A thermal manager manages the temperature and battery monitors. The battery monitor
measures the temperature of various software subsystems and hardware.
The thermal management software manages the chip temperature limits (typically, 85°C to 95°C)
and external device skin temperature limits, which are approximately 40°C for metal cover and
40°C to 45°C for plastic cover.
Figure : Software thermal management workflow

The following are some of the key elements of thermal management:
- Thermal core
- Thermal core manages the device skin temperature (Tskin) for any PCB, and
on-die sensors
- Thermal core and hardware control the junction temperature (Tj) for the
chipset and the PMICs
For more information on thermal core framework, see [Thermal core framework](https://docs.qualcomm.com/doc/80-88500-4/topic/54_Thermal_core_framework.html)
- Sensors
- Sensors on the chipset die
- Board thermistors – PMIC, PA, XO, and so on
- Management devices
- Passive cooling applied by reducing performance
- Device selection and threshold can be configured to tune for ID variability through a
configuration file
- Architecture
Figure : Main components of thermal management software

- User space – Custom Tskin rules, application-level awareness
- Kernel – Core isolation
- Limits hardware – Time critical mitigation for high and low junction temperature
and/or current
- **[Overview of boot thermal management](https://docs.qualcomm.com/doc/80-88500-4/topic/53_Boot_thermal_management_algorithms.html)**
Boot thermal management (BTM) ensures that the temperature is in a valid operating range before allowing the device to boot.
- **[Thermal core framework](https://docs.qualcomm.com/doc/80-88500-4/topic/54_Thermal_core_framework.html)**
The thermal core is part of the upstream Linux solution for thermal management. It helps in monitoring and identifying instances of inadequate power supply so that the thermal mitigation action can be applied.
- **[Limits management hardening](https://docs.qualcomm.com/doc/80-88500-4/topic/55_Limits_management_hardening.html)**
The limits management hardening (LMH) is a hardware-based protection circuit.
- **[User space thermal engine](https://docs.qualcomm.com/doc/80-88500-4/topic/56_User_space_thermal_engine.html)**
In the user space, the thermal engine has reworked the thermal daemon to enable integration with the sensor manager and allow for multiple algorithms to run in parallel.
- **[Thermal mitigation](https://docs.qualcomm.com/doc/80-88500-4/topic/57_Thermal_mitigation.html)**
The thermal engine implements thermal mitigation measures to prevent damage and failure when the device overheats.
**Parent Topic:** [Thermal](https://docs.qualcomm.com/doc/80-88500-4/topic/50_Thermal.html)
Last Published: Aug 18, 2023
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