Get Powered Up With USB-C
June 15, 2023
Sponsored Blog
USB charging has become the de-facto method for charging several portable devices we use these days, most notably smartphones, notebooks, and tablets.
Interestingly, the original USB standard, introduced way back in the mid-1990s, had nothing to do with charging. It was only intended for data transfer between the peripheral and the host. As the technology became more mainstream, USB-power delivery (USB-PD) protocols for battery charging were added to the specification in 2007.
Charging Up
An early example of mass adoption of USB charging was Apple’s iPod, which used a USB cable to charge the device back in 2001. In 2007, the USB Implementers Forum (USB-IF) released the USB Battery Charging (BC) 1.0 specification, which standardized how devices should charge and communicate simultaneously over USB. Over the years, the USB Power Delivery (PD) spec has become increasingly popular, enabling higher power output and faster charging speeds for compatible devices
USB power levels have risen from a fixed 5 V, 500 mA in the early version of the spec, up to a maximum of 20 V, 5 A in the USB 3.0 spec. The most recent major change was in 2021 with the USB PD 3.1 specification, which took USB charging to a completely different level, allowing up to 48 V, 5 (240 W) over a full-featured USB Type-C cable and connector. Now, multiple devices can be connected to a USB-C charger concurrently, with the ability for each device to draw relatively high power levels.
Why do we need so much power from the USB port? If you think about what’s being plugged in, often at the same time, that answer becomes obvious pretty quickly. Our everyday devices range from notebooks, smartphones, tablets, external hard drives, gaming controllers, and AR/VR headsets on one hand, to a new market for USB-C charging in power tools and e-bikes on the other.
As a leader in power electronics, Infineon offers a range of USB-PD controllers through its EZ-PD product family. The EZ-PD CCG3 is an example of a USB Type-C port source controller with power delivery. It complies with all the latest USB PD power profiles. Hence, it can be used in myriad applications, including power adapters, power banks, Type-C dongles, Thunderbolt accessories, monitors, docks, and notebook computers. The device, based on a 32-bit ARM Cortex-M0 MCU, is a programmable solution, and its dual 64 kbytes of flash memory can be used for fail-safe firmware upgrades at any time.
Adding a Layer of Complexity
Designing higher-power USB ports can be more complicated than standard USB ports as some new considerations come into play, including heat dissipation, power delivery, compatibility, and regulatory compliance with all applicable standards.
Another device aimed squarely at the USB charging port is Infineon’s EZ-PD CCG7DC highly integrated dual-port USB Type-C PD solution with integrated buck-boost controllers. It complies with the latest USB Type-C and PD specifications and is targeted for multi-port consumer charging applications. The programmable part is designed with a 32-bit Arm Cortex-M0 processor, 128 kbytes of flash memory and various analog and digital peripherals such as ADCs, PWMs, and timers. Dynamic load sharing enables the intelligent redistribution of the power budget between ports based on load conditions.
Keeping It Cool
As power through chargers increases, heat dissipation is an obvious issue. Managing heat flow is critical to prevent damage to the device and the USB port itself. In terms of the power delivery, it’s also vital to deliver the precise amount of power without exceeding the maximum current ratings provided by the USB-PD standard. Hence, the deployment of Gallium nitride (GaN) devices is a natural fit.
At a high level, the use of GaN devices in chargers offers higher efficiencies, smaller sizes, and faster switching frequencies. For example, Infineon's CoolGaN integrated power stage (IPS) combines the robustness of the 600-V GaN hybrid-drain-embedded gate injection transistor (HD-GIT) structure with integrated EiceDRIVER gate driver technology in a single QFN package.
USB has moved from a simple data-transfer mechanism to an invaluable feature in portable electronics. The ability to simultaneously charge battery-operated peripherals and other end devices up to reasonably high power levels has become an expected feature on today’s host devices.
