USB Type-C for Machine Vision

This article was first published on Quality Magazine, December Issue.

What is USB Type-C?

USB Type-C, also known as USB-C, is the latest USB connector developed by the USB Implementers Forum (USB-IF). It was designed to gradually replace all previous USB connector types¹, including USB Type A, Type B, Mini and Micro USB. Since 2015, USB Type-C has been widely adapted in a great number of laptops, mobile phones, and storage devices in the consumer electrics market. It allows those devices to transfer data faster while staying in a much smaller form factor.

Recently, the acceptance of Type C for industrial applications, such as machine vision cameras, medical imaging sensors, 3D capturing devices, etc., has been accelerated.

Why USB Type-C is better?

Continuing using the USB Type-C connector, the newly released USB 3.2 specification³ will support dual channels of USB 3.1 Gen 2 10G data transfer, which will add up the total bandwidth of data throughput to a maximum of 20 Gbps. To utilize this 2x USB 3.1 Gen 2 approach, the interconnection must go through a Type-C to Type-C full feature cable. According to ASMedia, a silicon vendor who is currently developing the USB 3.2 PHY controller, the first USB 3.2 device will hit the market around 2020⁶.

Efficiency Instead of using the 8b/10b encoding as in USB 3.0/3.1 Gen 1, USB 3.1 Gen 2 uses a more efficient 128b/132b encoding which reduces the encoding overhead. Thus a USB 3.1 Gen 2 Type C cable can support up to 9.7 Gbps in actual data rate which is more than double of a USB 3.0/3.1 Gen 1 cable’s actual speed at around 4Gbps.

Ample Power USB Type-C can deliver much more power up to 100W at 20V/5A to devices. Compare to the previous USB fixed power profile, USB 2.0 at 5V/0.5A and USB 3.0 at 5V/0.9A respectively, USB Type-C can supply power with various power delivery profiles to many different types of devices such as external storage drives to laptop computers etc. In the past, for some industrial cameras with high power consumption, they normally need a separate power input. Now with Type C, they can be bus-powered without any external power source.

Type-C Locking Connector

In the past years, some industry groups came up with their own USB connectors with locking mechanisms. For example, machine vision industry group had developed USB3 Vision locking connector standard in order to secure the USB interconnections for machine vision applications⁵.

The short length of Type-C cables does impose limitation to the adoption of Type C for industrial applications such as machine vision and professional audio and video applications that require long range connections. Currently, to overcome the length barrio of Type C applications, companies are putting tremendous efforts for developing long range active repeaters or extension cables with Type C features. As an example, later this year, Newnex plans to introduce USB Type C enabled repeater extending over several hundred meters.

Future of USB Type-C in Machine Vision

With all the advantages brought by USB-C and the emerging USB 3.2 standard, USB Type-C connector will probably turn into the only remaining USB port, though it will still take a few more years for the Type-C to be as popular as the Type-A on the host side. For industrial applications, we will definitely see more and more peripherals such as machine vision cameras to be featured with Type-C port.