This is exactly the same as the laptops have a power brick, or desktops have a PSU. It's relatively dumb AC/DC switch mode power supply (say ~90-230 to 18VDC) w

This is exactly the same as the laptops have a power brick, or desktops have a PSU. It's relatively dumb AC/DC switch mode power supply (say ~90-230 to 18VDC) w/o any major care about ripple (100mV ripple is amazing already) or even exact voltage. The monitors do have more voltage regulation inside.