Re:Intel is changing the future of power supplies with its A...
by numpad0 on Tuesday March 10, 2020 @12:35AM
(#22532751)
Why is it 19V for laptops? I had suspected it’s to compensate for voltage drop at linear regulators. Batteries are either 11.1(3.7v 4 cells) or 14.8(3.7v 3 cells 1-3 parallel) and these voltages doesn’t seem immediately consistent with ATX12V to me.
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Re:Intel is changing the future of power supplies with its A...
by thehobgoblin on Tuesday March 10, 2020 @05:27AM
(#22533998)
The nominal voltage of a battery isn't the maximum voltage, 3.7V lithium cells are typically charged to around 4.2V.
A 4S battery (or equivalent) will have a nominal voltage of 14.8V and a maximum voltage of 16.8V, which leaves 2.2V extra, probably to account for losses.
Why 19V ended up being the typical voltage rather than rounding it up to something like 20V or 24V is beyond me (probably a matter of compliance, try checking IEC 60950-1 or related standards).
Re:Intel is changing the future of power supplies with its A...
by cesarb on Tuesday March 10, 2020 @06:31AM
(#22534292)
I have seen many laptops where the charger sticker says the output voltage is 19.5V. And the nearest USB-C standard voltage is 20V, so that's probably what most newer laptops which charge through a USB-C socket use.
Re:Intel is changing the future of power supplies with its A...
by guerrilla on Tuesday March 10, 2020 @04:39AM
(#22533781)
I don't think we'd want to put those in our laps if they were dropping that much over linear regulators... Roughly (Dropped Voltage)*(Current through regulator)=(Power Dissipated)