Laptop cooling pad: Another instance of USB as a pure power source

I saw this cooling pad for laptops at Costco recently (from Belkin, $20), and picked it up to see how it’s powered: It runs off power from the USB port. It’s becoming increasingly common to see the USB port used purely as power source even when no data exchange takes place.  While many battery charger circuits relay on USB for power, this laptop pad is an example of USB used only for direct dc power. And now that the Chinese are standardizing on USB as an alternative to wall warts for dc power, this trend will only accelerate.

The cooling pad is simply a mounting pad for a laptop that provides a gap between the bottom of the laptop and the top of the pad, allowing thepad’s fan to blow up onto the laptop and force hot air out at the sides. According to this review,  the pad dropped the average temperature of the bottom of the laptop from 93°F down to 86°F, and the bottom of the pad – the part that comes in contact with your lap – dropped down to 81°F. 12 degrees is enough of a change to make a laptop comfortable on a warm day, but it would be much nicer if the laptop was more power-efficient its cooling designed so that no pad was necessary in the first place.

USB-to-5V cable.