With the popularization of Type-C interface on mobile phones, computers and other portable devices, the following problems may be encountered in daily use.
Why does this Type-C charger charge so slowly?
Can the Type-C charger of the computer charge the mobile phone?
PD charging? Type-C charging? What's the difference?
To answer the above questions, it is necessary to understand the basic design.
Fast charging VS slow charging
Ordinary charging, use the USB Type-A Standard interface to USB Type-B Micro interface cable to charge the mobile phone.
The USB Type-A Receptacle on the charging head is used as the power input terminal, and the USB Type-B Micro interface connected to the mobile phone is used as the power output terminal.
Without the blessing of the charging protocol, the charger can only provide a maximum charging power of 5V@900mA (USB3.0 is 900mA, USB2.0 is 500mA).
This is the hardware design specification of the USB Type-A/B interface, so this design provides a maximum charging power of 4.5W.
fast charging
In fact, whether it is a Type-C interface or a Micro USB interface, there have been products that support charging power exceeding the hardware interface design specification.
These are all thanks to the fast charging protocol, and most of them use the USB2.0 D+/- two lines in the adapter cable to complete the communication.
Note that the communication here is not USB communication, but a communication protocol designed using D+/- two wires. This kind of agreement is a private agreement, and the designs of each company are different. The detailed agreement will not be introduced in this article.
However, the principle of fast charging is negotiated through a private agreement, and the charger will increase the charging current or charging voltage to meet the fast charging of the device.
The mobile phone market is huge. Although each company uses the same Type-C interface as the charging interface, they have basically designed their own private fast charging protocol. 
The full name of PD is
Power Delivery, which is a fast charging protocol designed and promoted by the USB-IF Association to solve the chaotic situation of fast charging protocols for mobile electronic devices. The current PD3.1 protocol can support a maximum charging power of 240W, covering almost all mobile electronic devices.
To support PD fast charging, a USB-C to USB-C cable must be used, because PD fast charging is implemented based on the PD protocol.
The PD protocol is implemented on the Configuration Channel, which is A5 or B5 in the figure below.
There is no cc communication in the USB Type-A to USB Type-C charging cable.
As shown in the figure below, when the charging device is connected through the USB-C to USB-C charging cable, the cc of both sides will be connected.
After Power Negotiate, the charger will increase the supply voltage or current to achieve fast charging.
PD is relatively simple on Power Negotiate. The following is the cc communication on the Type-C interface of the laptop.
The Power Source side sends Source Capability (including 1-4 sets of Power Levels).
The Power Sink requests a suitable set of Power Levels according to its own needs. The Power
Source installs the Power Sink to request an increase in voltage and set the current limit threshold. The
charging demand of notebooks is generally 45W- 90W, so the Type-C interface is the first choice, and it also supports the PD fast charging protocol.
One USB-C port can realize the full function of USB+DP+PD.
Obviously, the Type-C charger used by the laptop also adopts the PD fast charging protocol, and it has 4 sets of power supply level declarations.
Then when using it to charge the mobile phone, the mobile phone can request the appropriate charging level.
Multi-protocol compatible
Private protocols have their own advantages, but are incompatible with each other. When the fast charging protocols on the Power Source side and the Power Sink side are inconsistent, it is like talking to a duck, and fast charging cannot be achieved.
UFP——PD sink side power-taking protocol chip, so that traditional small appliances can also be used for PD fast charging!
Ledry Technology launched LDR6328/LDR6328S power-taking terminal protocol chip, which is specially designed for the small home appliance market, allowing the traditional DC interface to be converted into a USB-C interface, supporting a maximum 20V5A, 100W input.
1 Overview
LDR6328 is a communication chip compatible with USB PD and QC developed by Ledry Technology Co., Ltd. for the USB PD protocol and Qualcomm Quick Charge (referred to as QC) protocol. The input terminal is mainly connected to the adapter of PD and QC, and the output terminal is configured to output a fixed voltage. The LDR6328 draws power from an adapter that supports USB PD and QC protocols, and then supplies power to the device. For example, you can configure the adapter
Output the required power to supply power to the wireless charger device.
2. Features
◇ Adopt SOP-8 QFN3*3 package
◇ Compatible with USB PD 3.0 specification and supports USB PD 2.0
◇ Compatible with QC 3.0 specification, support QC 2.0
◇ Can automatically trick PD to output 5V, 9V, 12V, 15V, 20V voltage, QC output 9V, 12V voltage.
3. Application
◇ All devices that need adapter (support USB PD and QC protocol) power supply
◇Fascial guns, kettles, kettles, desk lamps, smart speakers and other small home appliances
