Some points you must know about USB fast charge, Who determines the magnitude of the current?

Some points you must know about USB fast charge
With the rise of smart phones, the functions have gradually become stronger, and the battery capacity equipped has gradually increased. It turns out that the charging capability of USB can't meet the requirements of existing charging power and charging time. Today's smart phones and other USB devices are basically equipped with fast charging technology. Generally speaking, for USB charging power exceeding 10W (that is, 5V 2A) can be called fast charging.

Who determines the magnitude of the current?
The phone charging current is controlled by the phone, not the charger. The mobile phone will intelligently detect the load capacity of the charger. If the charger has large power and good quality, the mobile phone will allow the charger to load more current. The charger design output current is too small, so the mobile phone will limit the current it charges. For example, the maximum input of a mobile phone is 5V1.5A. When your charger is only 5V1A, it will cause the mobile phone to only charge with 5V1A current. Not only the charging speed is slow, but the charger will be hot at full load. If you charge The charger is 5V2A, the mobile phone will control only 1.5A input, the charger load is low, and there is sufficient margin.

In fact, 5V2A is what Qualcomm calls Ｑuick Charge 1.0 technology. Of course, in order to prevent the charger from being fully loaded, mobile phones are generally limited to about 5V1.8A. The charging technology of 5V2A for Android phones has no restrictions and no identification protocol.