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docs/kb/laptop-power-limit.md: add doc #1037
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| # Laptop power limits | ||
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| This article describes how power limiting works on Dasharo firmware for laptops. | ||
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| ## Power sources | ||
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| A laptop may be powered from AC, or from battery. Each of these two has a limit | ||
| on how much power it can provide. | ||
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| - AC barrel jack: Depends on the wattage of the included power supply | ||
| - USB-PD: Depends on the wattage rating of the specific power supply being used, | ||
| and on the contract that was negotiated between the laptop and power supply | ||
| - Battery: Depends on the maximum discharge rate specified by the manufacturer | ||
| and on charge level | ||
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| The Embedded Controller must observe what sources of power are present and | ||
| adjust platform power limits accordingly. | ||
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| To limit power, the CPU is throttled using the Psys power limit mechanism. This | ||
| ensures that the power draw does not exceed the limit, by proactively throttling | ||
| CPU performance. | ||
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| ## AC power limit | ||
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| This limit is a minimum of: | ||
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| - Power supply wattage x estimated power conversion efficiency | ||
| - Maximum current rating of the input power rail | ||
| - Wattage of the included AC power supply | ||
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| ## DC power limit | ||
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| This power limit is a minimum of: | ||
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| - Battery capacity x 1C discharge rate | ||
| - Maximum current rating of the battery power rail | ||
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1C? 1 cell?
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C as in C-rate: https://batteryuniversity.com/article/bu-402-what-is-c-rate
1C = complete discharge in 1 hour
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Maybe add the link, e.g.: