DESCRIPTION OF THE RELATED ART

Portable computing devices (“PCD”s) are becoming necessities for people on personal and professional levels. These devices may include cellular telephones (e.g., smartphones), tablet computers, palmtop computers, portable digital assistants (“PDA”s), portable game consoles, and other portable electronic devices. PCDs commonly contain integrated circuits or systems-on-a-chip (“SoC”s) that include numerous components designed to work together to deliver functionality to a user. For example, an SoC may contain any number of processing engines, such as central processing units (“CPU”s) with multiple cores, graphical processing units (“GPU”s), etc. An SoC may be coupled to other components within a PCD, such as system memory, wireless communication transceivers (also referred to as modems), power management systems, a charger integrated circuit (IC), touch-screen displays, cameras, microphones, speakers, etc.

In operation, the electronic circuitry within a PCD generates heat or thermal energy, which at excessive levels may be detrimental to the internal circuitry or, when conducted through the PCD case, could scorch a user's hand. The amount of thermal energy that is generated may vary depending upon the operating conditions. For example, processors may generate substantial thermal energy when operating at high workload levels or data rates. Also, power supply circuitry in the PCD may generate substantial thermal energy when the PCD is coupled to a battery charger.

One or more thermal sensors positioned within the PCD may be monitored to determine if the PCD or a portion thereof has reached a threshold or critical temperature. When a reading of the thermal sensor indicates that the PCD or monitored portion thereof has reached such a threshold temperature, an action intended to reduce thermal energy production or otherwise mitigate adverse effects of the thermal energy may be initiated. For example, the power (e.g., voltage and clock frequency) applied to a processor may be reduced. Using temperature measurements as feedback in a control loop to adjust how a PCD operates is sometimes referred to as “thermal management” or “thermal mitigation.” Adjusting voltage and clock frequency in this manner is sometimes referred to as dynamic clock and voltage scaling (“DCVS”). Such thermal mitigation techniques have traditionally been capable of restraining heat generation to a level below which excess heat can be safely dissipated by passive conduction through the PCD case into the ambient air.

In contrast with the type of thermal mitigation in a PCD described above, thermal mitigation in a desktop or laptop computer or similarly larger, less portable device may include actively removing heat from the device through the device housing or case, because there is space and adequate power source in the housing to accommodate active heat transfer features. For example, a desktop or laptop computer may include a fan that circulates air through ventilation openings in the housing. A desktop or laptop computer may include heat sinks, thermoelectric cooling devices, heat pipes, etc., because the heat can be channeled through the housing and dissipated into the external environment. In contrast, the sealed compact case of a PCD, the limited battery capacity, and the need to maintain the case at a temperature that is comfortable for a user to hold present particular challenges to thermal mitigation.

SUMMARY OF THE DISCLOSURE

Systems, methods, and other embodiments are disclosed for thermal mitigation in a PCD by active heat transfer to a docking device, such as a docking station, charging station, or other electronic device to which a PCD may be connected.

An exemplary system for thermal mitigation in a PCD may include a PCD case, a thermal coupler having a portion exposed externally to the PCD case, an active heat transfer system within the PCD case, a thermal sensor within the PCD case, and a control system within the PCD case. The active heat transfer system may have a first portion thermally coupled to a heat source component within the PCD case and a second portion thermally coupled to the thermal coupler. The active heat transfer system may be configured to transfer thermal energy from the first portion to the second portion when activated, and is activated based on a temperature measurement of the heat source component and when the PCD is coupled to a docking device.

Another exemplary system for thermal mitigation in a PCD may include a PCD case, a thermal coupler having a portion exposed externally to the PCD case, a thermoelectric device thermally coupled to the thermal coupler, a heat pipe, a thermal sensor within the PCD case, and a control system within the PCD case. The heat pipe may have a first end thermally coupled to a heat source component within the PCD case and a second end thermally coupled to the thermoelectric device. The heat pipe may be configured to transfer thermal energy from the first end to the second end. The thermoelectric device may be configured to transfer thermal energy from the second end of the heat pipe to the thermal coupler when activated. The thermoelectric device may be activated based on a temperature measurement of the heat source component and when the PCD is coupled to a docking device.

An exemplary method for thermal mitigation in a PCD may include obtaining a plurality of temperature measurements associated with a heat source component of the PCD using a thermal sensor within a PCD case, determining whether the PCD is coupled to a docking device, and activating an active heat transfer system within the PCD case based on at least one of the plurality of temperature measurements when the PCD is coupled to the docking device. Activating the active heat transfer system may include transferring thermal energy from a first portion of the active heat transfer system thermally coupled to a heat source component within the PCD to a second portion of the active heat transfer system and to a portion of a thermal coupler exposed externally to the PCD case.

