Introduction:
When it comes to connectivity between devices, USB is considered the standard in wired connectivity. The last major update in USB standards was made with the introduction of USB-C connector. How much do you know about the USB Type-C connector? In this article, we will discuss the anatomy of the UCB Type-C and its modes. This USB is capable of both data transmission and power delivery. It is also flippable and has many important features we will take a look into. But first, let us define the USB-C.
The USB Type-C:
The USB Type-C (also known as the USB-C) is a 24-pin USB connector system. It can provide high-speed data transfer up to 10GB/s and power delivery of up to 100 W.
USB Type-C Features:
The USB Type-C interface has three main features:
- It consists of a flippable connector so it can be flipped relative to the receptacle.
- It can support previous USB standards (USB 2.0, USB 3.0, USB 3.1 etc.) and third-party protocols (DisplayPort, HDMI) in the Alternate Mode.
- Using this interface the device can choose the appropriate level of power flow through the interface.
The USB-C Receptacle/Pins:
The USB-C Connector has 24 pins for the receptacle and plug as mentioned before.
Figure 1. The USB Type-C receptacle. Image courtesy of Microchip.
Figure 2. The USB Type-C plug. Image courtesy of Microchip.
The USB 2.0 Differential Pairs:
The differential pairs used for USB 2.0 connectivity are the D+ and D- pins. The two D+ and D- pins in the receptacle are connected to each other and only one USB 2.0 data differential pair available. This is for the ‘flippable’ function.
The Power and Ground Pins:
The VBUS pins and GND pins are the power and return paths respectively. The default voltage for VBUS is 5V but you can use other than the default value for different devices. The VBUS can conduct up to 20 V with a maximum current of 5 A and therefore can deliver maximum power of up to 100 W. This can be used for charging larger devices that demand more power. This means the USB Type-C is adaptable to power requirements with respect to devices.
The RX and TX Pins:
There are two sets of RX and TX differential pairs. One of the RX pairs and a TX pair can be used for the USB 3.0/3.1 protocol. A multiplexor is used to re-route the data from the differential pairs through the cable since the USB is flippable. Also, note that the minimum feature set of USB-C does not include the USB 3.0/3.1 and can be used through the Alternate Mode.
The CC1 and CC2 Pins:
The CC1 and CC2 pins are the Channel Configuration pins. They allow cable attachment, removal detection, receptacle/plug orientation detection, current advertisement etc. They can also be used during the power delivery and alternate mode for communication.
The VCONN Pin:
The USB-C is used for fast data transfer and power flow. This feature takes the use of special chips inside cables. Some active cables also use a re-driver chip to strengthen the signal and to overcome losses. This can be done by supplying a 5V, 1W power supply to the VCONN pin inside the cable. The active cable will use a Ra resistor to pull down the CC2 pins. After the cable orientation is determined the channel configuration pin will be connected to a 5V, 1W power supply to power the cable. Hence the CC2 pin is connected to power supply VCONN.
The SBU1 and SBU2 Pins:
These two pins are used in the Alternate Mode as low-speed signal paths.
The USB-C Power Delivery:
The USB-C can help in choosing the appropriate power flow through the interface. These power negotiations take place through the USB Power Delivery Protocol. Usually the sink will send a request to the source and adjust the VBUS voltage as required. The source will stabilize the VBUS voltage and then send a ‘power-supply-ready’ message to the sink. The sink will request and the source will provide and send a ‘power-supply ready’ message again. Other power negotiations such as in the Alternate Mode are also made using the Power Delivery Protocol on the CC line of the standard.
USB-C Alternate Modes:
The Alternate Mode allows for the implementation of third-party protocols (DisplayPort, HDMI etc.) The Alternate Modes will support the USB 2.0 and USB Power Delivery Connection.
Conclusion:
The USB Type-C is truly becoming the universal standard in modern devices and is a worthy upgrade. With its ability to transmit data and power faster and efficiently, it won’t be much time before it replaces older USB versions.
