Changing the Rules of Engagement in USB

Changing the Rules of Engagement in USB

It is now a quarter of a century since universal serial bus (USB) first arrived on the scene. With several billion ports currently in operation globally, and many more being added each year, its market traction is unmatched by any other interface technology. The advent of USB Type-C has meant that it has a very prosperous future ahead of it too. Through the reductions in size that this connector format enables, marked space savings can be made. Furthermore, thanks to the 10Gbps data rates now supported, it poses a serious rival to a broad array of different I/Os (thus presenting the prospect of system simplification being benefitted from and development projects being completed quicker). As Type-C is orientation agnostic (with no keying involved), the user frustration associated with previous USB connectors is completely avoided.

Because of all these characteristics, Type-C is accentuating the appeal of USB - with implementation into modern consumer electronic designs proving greater than ever. OEMs are able to produce more streamlined designs that deliver heightened degrees of operational performance, as well as greater convenience. From a user perspective they no longer need to keep numerous dedicated chargers/cables for different items of equipment (each using proprietary connectors with no cross compatibility). This is of real value ecologically too, since it significantly reduces the build-up of e-waste.    

Through Type-C connectivity’s arrival, the latest version of the USB Power Delivery (PD) specification has further strengthened this interface protocol’s position. It means that up to 100W of power (and 5A of current) output can be carried. This takes USB beyond just simply providing charge to smartphones or powering computer peripherals, enabling things to be achieved on a much grander scale. Now there is the capacity for household appliances, lighting installations and power tools to run off it. The bi-directional nature of this specification means that any connected equipment can, depending on its circumstances, either act as a sink or a source (drawing power or providing it). The direction that the current is flowing has no effect on the way that data flows (this can go in the same or in the opposite direction). However, such a huge increase in power levels will bring up difficult engineering challenges. Among the areas where system design implications will be witnessed are in respect to thermal management, circuit protection, PCB utilisation, etc. Also, given the accelerated data rates made possible, issues relating to maintaining signal integrity need to be addressed.

Toshiba compiled a highly informative white paper to help engineers looking to implement USB Type-C functionality into their designs. This covers essential design factors that must be considered, and what hardware will be required.

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