# Thermal

Source: [https://docs.qualcomm.com/doc/80-88500-4/topic/50_Thermal.html](https://docs.qualcomm.com/doc/80-88500-4/topic/50_Thermal.html)

Thermal management is done using the tools and technologies that maintain the system
    temperature within a specific range to prevent overheating.

The table lists the tools and technologies used for thermal management on the QRB5165
          device:| Tools/Technology | Description |
| --- | --- |
| Thermal sensors | 25 sensors (TSENS) sensors |
| VDD restriction | The limits management hardware (LMH) manages the VDD in hardware instead of<br>                software. |
| Battery current limiting (BCL) | <ul class="ul" id="Thermal_50__ul_itr_jjb_gxb"><br>                  <li class="li">The codec takes a predetermined and programmable response in both attenuation<br>                    and attack time to the alarm level.</li><br><br>                  <li class="li">Helps deliver a product with capabilities to manage the scarce battery<br>                    resource across difficult concurrency use cases.</li><br><br>                </ul> |
| CPU cooling devices | <ul class="ul" id="Thermal_50__ul_ur3_jjb_gxb"><br>                  <li class="li">Core isolation is listed as a separate cooling device in the kernel (1 CPU<br>                    isolation cooling device per CPU).</li><br><br>                  <li class="li">CPU cooling device also handles frequency mitigation. </li><br><br>                  <li class="li">Separation of core isolation and CPU cooling devices allows for inclusion of<br>                    only one CPU cooling device per CPUFreq policy.</li><br><br>                  <li class="li">For example, there are 3 CPU cooling devices for CPU frequency mitigation –<br>                    cpu0, cpu4, and cpu7 respectively.</li><br><br>                </ul> |
| LMH DCVSh kernel driver | <ul class="ul" id="Thermal_50__ul_nkb_kjb_gxb"><br>                  <li class="li">The OSM CPUFreq driver sends the LMH mitigation notification to the<br>                    scheduler.</li><br><br>                  <li class="li">HLOS cannot change or view the hardware T<sub class="ph sub">j</sub> limits for CPU.</li><br><br>                  <li class="li">HLOS CPUFreq cooling device mitigation is now sent to OSM CPUFreq driver.</li><br><br>                </ul> |
| LMH voltage mitigation | <ul class="ul" id="Thermal_50__ul_tgh_kjb_gxb"><br>                  <li class="li">Voltage mitigation for CPUs is not managed by the hardware.</li><br><br>                  <li class="li">Voltage mitigation can be set manually by setting thermal policy in<br>                    consideration of voltage to frequency mapping for CPU.</li><br><br>                </ul> |

- **[Temperature sensors](https://docs.qualcomm.com/doc/80-88500-4/topic/51_Temperature_sensors.html)**  

A temperature sensor (TSENS) detects the change in temperature of the device.     Twenty-five sensors are placed near the hotspots of the silicon die.
- **[Software thermal management](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.

**Parent Topic:** [System](https://docs.qualcomm.com/doc/80-88500-4/topic/7_System.html)

Last Published: Aug 18, 2023

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