The ST-ONE is the world’s first digital controller to deal with an Arm Cortex-M0+ core, an energetic clamp flyback controller, and a USB Energy Supply 3.1 module inside the identical bundle. Mixed with our MASTERGAN energy levels, ST-ONE allows small chargers with an influence density of 30 W/in3. Comparatively, present fashions solely supply a 3rd of that. Our current demonstrations showcase a unit that appears and looks like a smartphone charger however can energy a laptop computer. Furthermore, we provide a growth board to make sure companions can design their merchandise quickly. Therefore, we anticipate the primary merchandise utilizing ST-ONE to be commercially out there by the tip of the 12 months or early 2023.
What does the hunt for larger energy density seem like?
Extra energy in the identical type issue
The introduction of GaN units got here with the promise of far larger vitality effectivity. Technically, it could imply two issues: chargers get smaller whereas delivering the identical energy or present extra energy out of the identical type issue. Wall chargers are distinctive as a result of they have already got gotten practically as small as they will. Producers should use prongs that match into the wall socket and respect worldwide requirements such because the creepage distance, which units the minimal area between two insulators. Such issues, subsequently, restrict how small a wall charger can get. Consequently, as engineers look to offer extra energy inside the identical type issue, GaN seems like a implausible resolution.
GaN energy units and new ICs
Gallium Nitride has a large bandage, making it a way more environment friendly energy gadget at excessive voltage. Its larger breakdown voltage and low on-state resistance primarily imply that it could help far larger hundreds inside a smaller gadget than a silicon various. Nonetheless, driving GaN energy units requires extra complexity to maximise the advantages of their excessive switching frequency. For example, circuits will need to have a steady provide voltage and keep away from spurious gate noises in any respect prices. After witnessing a few of the points engineers face, we wrote an utility be aware to supply the perfect suggestions for driving E-mode GaN units. The ST-ONE represents one other resolution to this downside by offering a singular all-in-one resolution.
What’s contained in the ST-ONE?
ST-ONE contains two main elements: a major and a secondary facet controller. The previous makes use of a high-voltage start-up generator that straight connects to the mains and may deal with spikes of as much as 800 V. It thus saves groups from including an exterior sensing circuit. Designers want a few diodes for the AC enter voltage, and the ST-ONE does the remaining. We even embody an X capacitor (X-Cap) discharge circuit, which is usually mandated by security rules. Moreover, the first facet contains the energetic clamp flyback that’s important for driving a GaN energy gadget. The controller operates at as much as 1 MHz and helps a low quiescent present for no-load consumption.
On the secondary facet, ST-ONE features a synchronous rectifier as an alternative of a extra conventional diode to enhance vitality effectivity. Equally, it features a 24 V N-channel load swap gate drive, so engineers don’t have so as to add quite a few exterior elements to disconnect the output voltage when utilizing a dual-role USB-C port. Furthermore, the ST-ONE displays our work on our USB-C PD ecosystem because it features a complicated energy supply controller able to supporting proprietary interfaces. The presence of a Kind-C PHY controller additionally simplifies design operations. Evidently, the secondary facet oozes optimizations to make sure larger effectivity, a shorter market time, and a decrease invoice of supplies.
Out of all of the elements on the secondary facet, the customized Cortex-M0+ core is undoubtedly one of many options that explains what made ST-ONE doable immediately. Certainly, utilizing a conventional STM32 would have been too expensive and too huge. Nonetheless, strengthened by our experience in microarchitectures and USB-PD methods, we designed a customized gadget that made such an built-in resolution viable.
The microcontroller contains 64 KB of flash, 8 KB of RAM, and a 12-bit analog-to-digital converter to manage each the AC/DC stage and the USB-PD protocol, thus dealing with the quick switching necessities of GaN units. We additionally included a finite-state machine that optimizes computations. Consequently, we are able to make a smaller die with fewer transistors whereas retaining optimum efficiency.
One other innovation that made the ST-ONE doable was the galvanic isolation between the first and secondary sides. Historically, engineers would use optocouplers. Nonetheless, by providing an embedded 9.6 kV galvanically remoted twin communication channel, the ST-ONE not solely homes either side underneath one roof however meets IEC 62368 certifications. Consequently, engineers utilizing the brand new all-in-one gadget are extra assured that their product will obtain regulatory approval in the event that they abide by our implementation.
The way to benefit from the ST-ONE?
To assist engineers get began, ST launched the EVLONE65W analysis board. It contains an ST-ONE and a MASTERGAN4. Focusing on 65 W functions, it may be a reference charger for shopper or industrial merchandise because the board opens the entire ST-ONE’s options. Designers might change the copper core with a planar transformer, amongst different issues, to shrink their design. The facility supply module additionally supplies 5 profiles out of the field. Moreover, it showcases the gadget’s safety measures, resembling over-current, over-temperature, overvoltage, or under-voltage protections, to call a couple of. The STDES-65ACFADP is the same reference design showcasing a peak effectivity of 93.7% and that makes use of a planar transformer with a MASTERGAN2.
Software program and GUI
ST is engaged on software program and a graphical person interface coming later to assist builders outline their profiles quicker. The code will move main certifications. Therefore, whereas regulatory our bodies demand that every closing product receive its certification, utilizing the ST code will probably be important to hastening that course of. The firmware can even assist designers add a second USB-C port to their design. Certainly, whereas the IC would wish an extra buck-boost for the second port, the ST-ONE could be configured to facilitate using an additional connector. The GUI can even assist benefit from the MCU’s finite state machines to make them extra accessible and hasten developments.