Preface

USB Type-C is a USB interface shape standard, which is smaller than Type-A and Type-B. It can be applied to both PC (master equipment) and external devices (such as mobile phones).

USB Type-C has 4 pairs of TX/RX branches, 2 pairs of USB D+/D-, and a pair of SBU,2 pieces of CC, as well as 4 pieces of VBUS and 4 ground wires.

The course of development

On October 4, 2022, the European Parliament overwhelmingly passed a bill stipulating that from the autumn of 2024, USB type-C (USB-C) will become the standard charging port for electronic devices such as smartphones, tablets, e-readers, digital cameras, headphones, handheld video game consoles and portable speakers sold in the European Union.

From 2026, USB-C will also become the standard interface for laptop chargers.

In October 2022, Apple confirmed on the 25th that it would comply with EU requirements and use USB-C charging ports for all smartphones from 2024.

PIN definition

To understand the principle of Type-C, we must first understand his definition of PIN. The Type-C port has 4 pairs of TX/RX lines, 2 pairs of USBD+/D-, and a pair of SBU,2 CC, as well as 4 VBUS and 4 ground wires.

Of course, if the receiver only needs DP signals, not USB 3.1signals, then DP can use all four pairs of TX/RX differential lines to do output, thus achieving the DP output of up to 4 lanes, providing total output bandwidth up to 32.4Gbps (each lane can output 8.IGbps), easily achieving 5Kx3K 60 frames of video, or even up to 8K × 4K 60 frames of video (4:2:0 data), this mode is DP only mode.

In addition, USB D+/D- signals are reserved for use by USB2.0 devices in order to be compatible with USB2.0,Type-C, so USB2.0 and even USB 1.0 devices can support front and back insertion only by using the interface of Type-C.

It is worth mentioning that the DP+USB2.0 pattern can be implemented using USB D+/D- in conjunction with the DP only pattern above.

DP occupies 4 pairs of TX/RX difference lines, and USB only uses D+/D-.

In general, USB2.0 differential signals are only connected to one side, because USB Type-C Plug does not have B6 or B7.

USB3.1 only uses two pairs of TX/RX differential lines as data wires, connect TX1/RX1 when forward inserting and TX2/RX2 when reverse inserting. You can see that in any case, there will be two pairs of differential lines that are not used. DP alternating mode is to load DP signals into these two pairs of “redundant” differential lines, so as to achieve USB3.1 + DP to work at the same time.

Type-C also provides 2 CC lines and 2 SBU lines.

CC line is mainly used for the communication of Power Delivery module (hereinafter referred to as PD). First of all, CC line is used to determine the direction of equipment insertion: forward or reverse insertion, if it is forward insertion, the host uses CC1 to communicate with the device, reverse plug uses CC2, you can see that CC uses a single-wire protocol.

When the DP function is turned on, the SBU line is incarnated as the AUX_P/AUX_N differential line in the DP protocol (its polarity can be modified according to the positive and negative insertion direction), which is responsible for transmitting the DPCD,EDID and other key information of the equipment.

Technical characteristics

On January 7, 2013, the USB3.0 promotion organization announced at the American Consumer Electronics Show that the first batch of devices with transmission rates up to 10GB/s will be on the market in 2014. The USB interface of such products adopts the standard of USB3.1, namely Type-C interface.

The size of the socket end of the Type-C interface is about the slim design of 8.3mmX2.5mm; It supports the “forward and reverse plug” function that can be plugged from both sides, which can withstand 10, 000 repeated plug-ins; The standard cable with Type-C connector can pass through 3A current, and also supports “USB PD” beyond the existing USB power supply capacity, which can provide up to 100W of power.

USB Types

Type-A is the most extensive interface standard for computers and electronic accessories, which is the largest and most widely used in mouse, USB disk and data cable.

Type-B is generally used for external USB devices such as printers, scanners, USB, HUB and so on.

Type-C has a much smaller size than Type-A and Type-B, and is the latest USB interface shape standard. This interface has no difference between positive and negative directions and can be plugged in and unplugged at will.

Main characteristics

In order to meet the needs of data exchange, electronic devices provide USB interface, whether it is PC, tablet, mobile phone or even display device.

Almost without exception, there is a USB interface.

However, due to the limitations of technical standards, the USB plug is “directional”. If it is inserted in the wrong direction, it will either fail or break the interface or connector.

In this case, Apple has designed a Lightning interface for its device, and since it can be plugged in in both directions, users no longer have to worry about the wrong plug.

In addition to Apple devices, in fact, the industry has also introduced a similar interface standard: USB Type-C.

The USB Type-C trend was first led by Apple, and the new macBook will be USB Type-C.

This powerful technology has come into our view.

USB Type-C is an interface specification, which consists of Type-C plugs and Type-C sockets.

Among all kinds of mobile devices and PC, Type-C has become the most promising data interface.

With the gradual maturity of Tpe-C technology, all kinds of newly listed electronic products have chosen to configure full Type-C interface one after another in 2017.

In fact, the most intuitive advantage of Type-C is to completely get rid of the trouble of plugging. Its inherently excellent positive and negative pluggable interface design will not cause component damage after wrong insertion or error.

More importantly, the Type-C interface has a strong compatibility, so it has become a standardized interface that can connect PC, game consoles, smartphones, storage devices and expand all electronic devices, and achieve the unity of data transmission and power supply, such as the close combination of two display devices through a single Type-C cable.

In addition, Type-C supports the USB3.1 standard.

The maximum power supply of the standard is 100W, the voltage and current will be increased, and the coding consumption will be reduced from 20% of 3.0 to 3%.

In other words, users can transfer data and video quickly over Type-C, or recharge faster.

The standard also allows users to charge other devices with their own mobile phones.

As for the display, when using Type-C for data transmission, there is no need to use another power cable to power the display, which solves the problem of messy desktop wires, even the relatively high-end HDMI and DP interfaces can not be used.

Standard protocol

In September 2021, USB-IF released the latest USB Type-C interface and cable v2.1 standard protocol, which increased the power supply capacity from 100W to 240W, and future games do not even need a separate power adapter.

According to Apple Insider on April 21, 2022, EU officials voted for a long-planned proposal for Apple and all technology companies to adopt USB-C as a universal charger and add new requirements for wireless charging standards.

Report data

In Omdia “2021 USB Type-C Report”, research firm Omdia found that almost 80 per cent of laptops and almost half of smartphones had USB-C ports in 2020, and the adoption rate of both devices is expected to continue to grow.

The adoption of these core devices has driven the adoption of satellite equipment and opened the door to new uses such as portable desktop displays and general-purpose docking stations.

Laptops and smartphones are the core devices that are most likely to provide full-function USB-C, and power, data and audio-visual signals can be obtained through a single line.