GoKawiilIn the late 20th century, peripherals such as keyboards, headphones and storage devices required various cables and connectors to connect to computers. The industry needed to simplify and consolidate those connectors — and, with its introduction in 1996, the Universal Serial Bus (USB) standard began to establish itself as the default choice for electronic devices.
However, the connector’s predictable, interoperable plug and small size were merely its most visible advantages. USB also became an industry standard for powering devices — and its importance has only increased as rechargeable devices such as smartphones have proliferated with ever-expanding battery capacity. Each iteration of USB has improved its ability to deliver power faster — and more improvements are coming soon.
USB Power Delivery (PD) and USB Extended Power Range (EPR), the next steps in the technology’s evolution, are set to create faster, more powerful wired connections. USB PD and EPR have implications for a range of media modules across markets as disparate as automotive, consumer devices and commercial aerospace.
Many manufacturers’ design specifications for upcoming hardware incorporate the newest standards, and some are already on the consumer market. Certified products are expected to arrive by 2029, bringing faster device charging and data transfer to OEMs and the consumers they serve, as well as to other markets, including the manufacturing and defense industries. Anyone planning strategy for electronic devices should be aware of where things stand, with special attention paid to charging features.
The Power of USB-C
Early charging capabilities were limited. USB 1.1 (USB-A) could supply a trickle charge, with 0.5W of power. USB 2.0 brought the power level up to 2.5W, but a non-USB adapter would still charge a cellphone faster. USB-C, released in 2014, introduced a 15W power supply.
The USB PD protocol, announced in 2021, works with certified USB-C cables and connectors, enabling devices to negotiate for optimal power delivery. USB PD supports up to 100W — a huge jump — which it accomplishes by increasing the voltage step from 5V to 20V while keeping the electric current the same on USB-C cables. USB PD also supports bidirectional charging.
USB EPR builds on USB PD to support charging higher-power devices — including some laptops, monitors and other peripherals — via a single USB-C port. With USB PD and EPR, fixed voltages enable up to 140W, 180W and 240W power levels. An adjustable voltage supply mode permits devices being powered to request intermediate voltages, starting at 9V and increasing up to 48V.
Optimizing the connection to provide the maximum power and functionality is an electronic negotiation process that touches on everything from the device’s ambient temperature to adjustments to maintain the correct voltage. But in the end, the device being charged requests power, and the charging device can supply only up to the requested amount.
Any advance in charging technology is meaningful. For example, consider a consumer electronics device that supports up to 40W wired charging over USB-C (when using a USB-C PD charger that has the appropriate rating). With a certified charger and cable, the device could reach a 50 percent charge in about 20 minutes — a clear improvement over previous generations of such technologies, which would often take hours.
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