What are the factors constraining how small we can make switch mode power supplies of a given power rating?

Question

Why is it that low-wattage phone chargers are always smaller than higher wattage laptop chargers, which are always smaller than even higher wattage desktop PC power supplies? Aside from standards requiring some power supplies to have certain physical dimensions, what’s limiting our ability to make switch mode power supplies smaller than they already are while delivering the same amount of energy, and how might we get around those limitations in the future?

In: Engineering

Answer 1

Heat. The more power you put through one, the hotter it is going to get. The power supply needs to be larger in order to dissipate the heat without frying itself, not to mention higher current requires larger wires and beefier connections/electronics.