TECHNICAL-GUIDE
USB-C Charging
The Universal Demand and its Technical Guide The Need of USB-C Charging Globally
Benoit Foret
Senior Product Marketing Engineer, STMicroelectronics
With the growing adoption of USB-C, temptation to upgrade micro-B port with USB-C by simple connector replacement and schematics inherited from legacy devices is high. Some companies are sadly experiencing quick implementation hurdles which is finally making companies to re-design their device.
Addressing the Problem and Identifying its Solution
Legacy USB used to be hot sockets (5V always available on VBUS power pin), while clean USB-C implementation require cold socket implementation (VBUS line not powered until a sink is detected by the source). This means that direct access to the battery charger is impossible until the interface IC makes the decision to do so. Somehow, this is the right way to proceed, as USB-C connector is the same for SINK and SOURCE. Taking into account that charging power is scalable (from 2.5W to 100W) and can be also bidirectional, we’d better rely on dedicated controllers to ensure that connected devices are compatible together (ie. an AC adapter and a smartphone for instance), and working as expected (AC adapter delivering 5V by default, and not 20V). To do so, controllers must implement protocol features but also application features. Protocol could be even implemented by software, reporting the power management issues and interoperability ownership at system level, which is the most appropriate. Indeed, what really makes the value of a controller are the application features, which guarantee effective and certified implementation in the system and appropriate behavior when devices are operating in normal conditions of course, but especially when unwanted situation occurs.
Smartphone manufacturers are officially under pressure from the European Parliament to adopt USB-C universal charging as reported by the BBC. As Brussels is adopting USB-C in EU regulation, users will benefit a lot from this technological and political push: the possibility to charge everywhere, and at anytime, any kind of portable devices, making everyone’s life easier. Whereas the need for reducing electronic waste gained painfully people’s mind in the last 10 years, it has recently transformed into an everyone’s duty to limit overall men’s environmental impact. This is one of the Covid-19 lesson’s learns.
Creating Newer Innovation of Opportunities for Companies Some companies have understood it, and can see also in this realization an opportunity to stick with society’s mood, without engaging extra cost induced by a new regulation. Cost penalty for transforming once a charger into a universal one is balanced by the cost savings of making regularly proprietary chargers: no need to design, manufacture, package, transport and sell a charger for every device. Chargers are compulsory accessories to make devices work, but add extra cost, extra time, extra weight that never make anyone preferring a device to a competition one: no value in the act of purchasing, just extra wastes for the seller. Some famous companies started to sell their device on the market without including any AC adapter, but just a cable. A good example is Fatboy with its successful Edison the Petit portable lamp, having embraced the “no charger included” policy as a contribution to its sustainability program. More and more articles regularly report that both Apple and Samsung might be adopting such a philosophy starting from 2021.
People Ready To Buy Their Universal Charger
Not only smartphones makers are concerned by universal charging. This is how USB-C becomes a game changer: any kind of small portable device is eligible to 15W USB-C charging: computer and smartphones accessories of course, but also Bluetooth speakers and audio headsets, hearing aids and other medical devices, payment terminals or Wi-Fi access points, wearable devices such as smartwatches, healthcare devices
36 10 | 2021 BISinfotech
