Making USB Universal: New Devices Aim to Boost USB Charging Power
With the release of the USB PD 3.1 EPR standard, industry leaders are rapidly announcing solutions for more efficient USB power supplies.
Several companies, such as STMicroelectronics and Efficient Power Conversion, have announced new devices built to meet the new USB Power Delivery (PD) 3.1 standard. Since its conception, USB PD has captured the attention of designers and consumers alike. The advantages provided by the 3.1 standard may allow USB charging to become considerably more universal.
The increased power afforded by the USB PD 3.1 standard may power handheld devices or electric motors, all from the same adapter. Image used courtesy of Satechi
One of the most attractive features of USB PD 3.1 is its extended power range (EPR), which raises the upper limit for power delivery to an astounding 240 W. This increased range now gives USB PD the opportunity to not only provide faster charging for mobile devices but also provide power to high-performance or power-hungry devices such as computers or televisions.
The increase in available power calls for new and innovative devices to effectively control and regulate the output of a USB PD supply. This article takes a look at two recently announced devices that are built to enable efficient USB power supplies and the benefits they can provide.
ST-ONEHP First To Be Certified by USB-IF
The first USB PD device we’ll discuss is the ST-ONEHP from STMicroelectronics. Claimed as the “world’s first certified by USB-IF” to meet the USB PD 3.1 standard, the ST-ONEHP is a digital controller that, with a handful of other components, can help to trivialize the design of a USB PD source up to 28 V and 140 W.
Under the hood, the ST-ONEHP includes an embedded Arm Cortex M0+ core, an efficient high-frequency switching topology, and a USB PD communication interface. The devices come pre-loaded with certified USB PD firmware, giving designers a head start in qualifying their products.
Typical application schematic for the ST-ONEHP showing that, after integration with supplementary devices, a simple yet efficient USB PD source can be realized. Image used courtesy of STMicroelectronics
ST suggests integrating the ST-ONEHP alongside its MasterGaN half-bridge driver to reap the benefits of increased thermal performance and switching efficiency. In the EVLONE140W reference design, ST reports a peak efficiency of 94% and a whopping 25 W/in3 volumetric power density, giving the impression that USB PD 3.1 stands to make the next generation of USB supplies smaller and more efficient.
EPC Buck Converter Leverages USB PD 3.1
While a highly efficient source is certainly an achievement, it requires a highly efficient sink in order to see the most performance improvements. On the other end of the power supply chain, Efficient Power Conversion (EPC) has announced the EPC9177, a digitally controllable synchronous buck converter that can take the increased voltages allowed by the USB PD 3.1 standard and convert them into a 12 V output while delivering up to 20 A continuously (240 W).
The EPC9177 reference design leverages the EPC23102 chip to accomplish buck conversion with an efficiency of up to 97%. Image used courtesy of Efficient Power Conversion
Also taking advantage of the benefits of GaN, EPC’s new USB PD sink leverages GaN to accomplish fast and efficient switching—two prerequisites for an efficient buck converter. Interested designers can evaluate the EPC9177 via a reference design, available now from Digi-Key.
More Uses for USB
USB-C is proliferating in the smartphone industry. From 2019, the percentage of non-Apple smartphones using USB-C is expected to grow from 33% to nearly 100% due to its highly attractive characteristics.
Apple is rumored to include USB-C as part of the iPhone 15, though this remains unconfirmed by Apple itself. The new products from ST and EPC may allow designers to rapidly develop and test the next generation of power supplies. In addition, as GaN processes become more accessible and GaN devices become smaller and smaller, we may see even more efficiency gains in a short amount of time, enabling higher voltages and higher performance.
