The flagship level of Android smartphones has begun to popularize the TYPE-C fast charging interface. This interface can be used in conjunction with the fast charging protocol to achieve fast charging of mobile phones. The charging power ranges from 10W to 18W, and even some manufacturers have achieved 65W This greatly improves the charging efficiency. Gone are the charging history of 8 hours or even 12 hours in the past, and the appearance of fast charging has promoted people's experience of using mobile phones. How does Type-C achieve fast charging? Let me Share with you the reasons for these 2 aspects of Type-C and fast charging protocol.

1. Definition of MicroUSB interface

Before Type-C, the commonly used interface was microUSB. This type of interface has 5 pins, but only 4 pins are used, namely VCC, GND, D plus and D-. D plus and D- are used for To transmit data, VCC and GND are used for charging. Due to the influence of the wiring, large current cannot be transmitted. The following figure shows the definition of the MicroUSB interface.

Therefore, the MicroUSB interface cannot achieve high current charging, so fast charging cannot be achieved.

2. Type-C hardware interface definition

The most direct understanding of Type-C is that people do not need to distinguish the direction of the plug when charging. In addition, careful friends may notice that Type-C has more pins. The following figure shows the pin interface of Type-C definition.

The TYPE-C fast charging interface has 4 pairs of power cables. By default, Type-C supports 5V\/3A charging specifications in hardware. With the support of the charging protocol, the theoretical maximum output power can reach 100W, which indicates that Type-C supports 5V\/3A charging specifications. Better than MicroUSB. So how does the Type-C interface achieve high-power charging? This requires the support of the protocol.

3. Fast charging protocol USB-PD

USB-PD is the name of the protocol, and its full English name is USB-PowerDelivery, or simply USB-PD. It is currently the most widely used, most widely used, and one of the most mainstream fast charging protocols. This protocol has a USB-IF resistance The formulation and specification of the value. Type-C can realize high-power charging and fast charging of mobile phones with the help of USB-PD. This protocol is very troublesome to implement. Fortunately, the semiconductor company has integrated the USB-PD protocol into the chip .The chip can be used when designing the circuit, but this requires a successful handshake when the charger and the mobile phone are connected, that is, mutual confirmation of the fast charging function, mutual compliance with the fast charging protocol, and then the fast charging starts. As shown in the figure below, it is The fast charging protocol chip in the charger.