Changes between Initial Version and Version 1 of ventana/thermal_management


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Timestamp:
10/31/2017 09:41:26 PM (5 years ago)
Author:
Tim Harvey
Comment:

restored from 10/10/2017 cache

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  • ventana/thermal_management

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     1[[PageOutline]]
     2
     3= Thermal Management =
     4This page is made to help create an understanding of thermal management on the Ventana product family.
     5
     6See also:
     7 * [wiki:DVFS Dynamic Voltage and Frequency Scaling of the Processor]
     8 * [wiki:ventana/power Ventana Power Consumption]
     9 * [wiki:faq#WhyarecertainareasontheboardwarmwithregardstotemperatureWhyismyboardhot FAQ - Why is my board running hot?]
     10 * [wiki:ventana/thermal ventana/thermal]
     11 * [wiki:enclosures enclosures]
     12
     13== Maximum Board Operating Temperature ==
     14Almost all Gateworks standard products are defined as industrial temp (see respective board datasheet) with an operating temperature of -40C to +85C with adequate airflow. This means that the components used on the board are all rated for that temperature range or better. Typically power consuming/heat-producing processors will have a max operating temperature that exceeds this specification.
     15
     16For example the following components are used on Ventana boards:
     17 * IMX6Q - Automotive temperature grade -40C to +125C
     18 * IMX6DL - Industrial temperature grade -40C to +105C
     19 * DDR3 - Industrial temperature grade -40C to +95C
     20
     21We are often asked for the max ambient temperature a board can be operated at. This depends on the following:
     22 * max temperature of the components on the board (you can't exceed any part's max operating temperature)
     23 * active airflow (which will help to reduce heat from components that are hotter than ambient)
     24 * enclosures (need to be able to dissipate internal heat to their environment otherwise over time the internal temperature keeps rising)
     25 * power consumption (which is a factor of what your application is doing on the board and what peripherals you have added)
     26
     27In order to determine the maximum ambient temperature you can operate at, you need to ensure that the components themselves do not exceed their max operating temperature. The components that consume the most power and thus produce the most heat are the ones that you want to focus on. If your board uses an Automotive grade CPU with a max operating temperature of 125C you can work backwards by raising the ambient temperature the board is operating under (within any intended enclosure) until the CPU has reached its maximum temperature. The difference between the CPU's internal temperature sensor reading and the ambient temperature is the thermal resistance of the board with respect to ambient. You will find that this value varies per board (depending on the board size, thickness, layers, copper) and also varies greatly on the power consumption (which varies depending on your application).
     28
     29This evaluation process needs to take place within the enclosure you intend to operate within. You will find that the smaller the enclosure the more difficult it will be to get heat out of the enclosure. This depends on the thermal resistance of the enclosure itself with respect to its ambient.
     30
     31Once you determine the max ambient temperature the board/system can operate within under your system parameters (peripherals, and application), you can do the following to increase this maximum:
     32 * increase airflow which helps cool the components that exceed the ambient temperature (such as the CPU, DRAM, power supply)
     33 * decrease the board's thermal resistance by adding or increasing the mass and surface area of heat-sinks