Power distribution inside the laptop

How laptop power distribution works

voltage regulator Okay, the power comes into the plug on the back of the computer. This connects it to metal traces inside the mainboard of the computer. These will be connected to voltage regulators which often output 5 volts, 12 volts, 3.3 volts, and the CPU voltage; they sometimes look like the image at right.

These will be connected to cylindrical capacitors distributed throughout the mainboard. Capacitors act like tiny, fast batteries, supplying extra power where needed to maintain a steady voltage during high demand.

Finally, power goes to all the devices that need it.

Power for the LCD display is usually done seperately. Generally, LCD backlights require high voltage to operate. A component that might be called a power inverter will step the voltage up to what is needed for the backlight. Sometimes this inverter is a discrete and replacable component, and sometimes just a chip on your mainboard. It is also involved in the brightness control.

The battery is an important part. It supplys power to the input-side of the voltage regulators, just like the power from the AC adapter. Additionally, there is a charging circuit, which uses the power from the AC adapter prior to the voltage regulators, to charge the battery. (By the way, this is why the AC adapter voltage is always rated higher than the battery's rated volatge-- you need higher voltage for charging.)

There is a separate page exclusively for Laptop Battery Problems.