With an estimated 9-10 billion ports in operation, Universal Serial Bus (USB) has become the most commonly used interface technology in modern electronics/computing designs. Though the standard continues to evolve, it needs to do so in such a way that delivers extra functionality while maximising compatibility with widely proliferated previous generations. Elevated power levels and accelerated data rates present a variety of new challenges, not least in terms of long-term reliability and signal integrity.
Capitalising on USB’s ability to transfer power as well as data (and the efforts of international legislation to eliminate proprietary power adaptors from portable electronic goods), USB connectivity has become a globally ubiquitous method via which to carry out recharging. Airports and hotels now have dedicated USB charging points in abundance, while in domestic environments ‘wall-warts’ are used to connect USB interfaces to the AC mains. As USB technology has progressed, the 5V supply that USB 2.0 originally offered (which translated into an output of 2.5W and was mainly for powering computer peripherals) has been expanded by a series of higher power charging profiles - with 10W, 18W, 36W, 60W and 100W subsequently added to the USB power delivery specification. Through these far more rapid charging of electronics equipment has been made possible.
The latest iteration of the USB standard, USB Type-C, is a small, versatile, reversible-plug connector that redefines integrated data, power and connectivity. USB Type-C connects to both hosts and devices, thus replacing Type-A and Type-B connectors and cables. Building on the continued success of the USB standards, USB-C combines the SuperSpeed USB 10Gbps (USB3.1) data rates and the USB Power Delivery (PD) specification with a new miniaturised, flippable connector and bidirectional cable specification that offers extra convenience and versatility for end users.
The sensitivity of its high-speed transceivers means that USB Type-C needs greater protection from the threat of electro-static discharge (ESD). This can be achieved using bi-directional transient voltage suppression (TVS) diode arrays.
From a power delivery standpoint, the substantial rise in power levels mandates more sophisticated power management. This means that designers need to source ICs with highly effective thermal shutdown, under-voltage lockout and over-current protection mechanisms. Furthermore, these devices need to have small form factors and low on-resistance - so they do not impact heavily on the size, overall power consumption, or thermal characteristics of the interface.
Toshiba has produced a whitepaper showing how advanced ICs and discrete components can be specified to tackle the challenges of implementing effective USB Type-C designs. To access this white paper, click here: