TECH-COLUMN
Benoit Foret
Senior Product Marketing Engineer, STMicroelectronics
USB-C Charging
The Universal Demand and its Technical Guide 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.
The Need of USB-C Charging Globally
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.
23 12 | 2021 BISinfotech
