Do laptops use ATX? If not, how do laptops turn off on their own after shutdown?

Thread Starter


Joined May 15, 2021
If not ATX, what other power interface is used to shut off a laptop's components after shutdown?


Joined Jan 30, 2016
Many laptops use a dedicated charging control chip plus 2 or 3 MOSFETs to control the flow of power between charger/AC supply (typically around 18 - 24v), battery, and the main motherboard switch-mode power regulators (eg backlight, 5v, 3.3, and now often 1.8v and down to sub-1v) . Usually there is a permanently-on low-current supply (typically 5 or 3.3v) for the charging control, soft-start, wake-on LAN/RTC, sleep/hibernate and other 'powered-off' actions.

The block diagram below shows the functions in a TI BQ24721 charger/battery management controller - but many IC manufacturers produce similar devices. The ATX/ACPI functionality in a desktop is quite crude by comparison.