USB type-c devices are also becoming more popular in the real world, and many popular mobile phones and tablets use the USB type-c interface. I expect that products using the USB Type-C interface will increase rapidly in the next few years.

Why is the power 15W (5V3A)?

In addition to plugs that can be plugged in both front and back, the USB Type-C adapter provides more power than any previous USB version. While USB Type-C can support up to 100W for USB 3.1 and USB charging, system designers must carefully select features to maintain a reasonable overall cost.

The USB Type-C interface uses 15W of power and is six times the standard USB 2.0 charging rate.

For most smartphones and tablets, 15W is enough and cost effective.

Diode rectification and PSR are widely used in adapters with currents below 2A

The normal power of previous mobile phone power adapters was 5V/2A or lower. Because of the simplicity, optical isolators and programmable references can be removed, and primary side regulation (PSR) is often used for AC/DC conversion. A diode rectifier is used at this power level because the load current is not high.