EYE on NPI - CUI Inc's 30 W Desktop USB PD Adapters #EYEonNPI @cuiinc  @digikey @adafruit
Channel: Adafruit Industries
Date: 21/06/2022

This week's EYE ON NPI is very adaptable - it's CUI Inc's 30 W Desktop USB PD Adapters (https://www.digikey.com/en/product-highlight/c/cui/30-w-desktop-usb-pd-adapters) which have up to 30 Watts of output with a variety of voltages, so they can be used in multiple product designs to make your inventory and procurement simpler! These power adapters will help you transition your products from DC jacks to USB C, which has power negotiation all in one consistent, well-recognized connector.

We've covered DC plug adapters on EYE ON NPI before. Just about every product in the world uses these ubiquitous 'barrel jack' connectors for power (https://www.digikey.com/en/products/filter/ac-dc-desktop-wall-adapters/130): often 5.5mm outer diameter / 2.1 or 2.5mm inner (https://www.digikey.com/en/products/detail/cui-devices/PJ-003A/96969). These connectors are so popular that they don't really 'mean' anything when you see them other than "power connector". There's no inherent voltage, polarity or current capability that is indicated by a barrel jack. You could have 5VDC center-positive 5A adapter (https://www.digikey.com/en/products/detail/cui-inc/SDM36-5-U-P5/8547877) or you could have a 9VAC 300mA adapter, all with the same connector. Only by careful reading and matching of the labels can you verify which adapter you have matches with which product - and if you lose the adapter it could be a real pain to get a replacement.

That's where USB Type C has a lot of potential to improve and simplify this issue: folks end up being scared to toss out their power adapters because you never know when you need it or what the matching devices is, even years later. If, instead, we had one power adapter and cable that would be usable for any product, that would deliver the right voltage, we could mix and match adapters without worrying about under-powering or over-volting. A lot of mobile devices have started to go this way with USB mini or micro B ports, cell phones being the most popular: all USB ports are basically 5V 1A (https://www.digikey.com/en/products/detail/cui-inc/SWI5-5-N-I38/5287192) and if you have something running off of a Lipoly battery, this is plenty to keep you topped up. But for larger devices, ones with displays or motors, or larger battery packs, 5W (or 10W on a fancy high current adapter) is not going to be enough. And you don't necessarily want 5V input! If you have a backlight that requires 12V or a battery pack that is 8.4V it's going to be expensive and wasteful to try and boost 5V USB up to 12V.

USB C's Power Delivery spec is a great solution: it can provide anywhere from 5V to 20V DC, at up to 100W if the power adapter is chunky enough. CUI's awesome blog has a great post about the power delivery specifications with clear text and diagrams (https://www.cui.com/blog/usb-type-c-pd-and-pps) for more info - in particular watch out that you have a current limitation or 3A or 5A at each voltage so you'll never be able to get 5V 20A = 100W. Instead you'd get 20V at 5A. However, if your voltage / wattage use case lies within the PD requirements, you're good to go! You can use a standard USB C connector (https://www.cuidevices.com/catalog/interconnect/connectors/usb-connectors), standard USB C power cables (https://www.cuidevices.com/catalog/interconnect/cable-assemblies/usb-cables?[0].sn=Connector%201&[0].sv=Type%20C%20Plug) - all available from CUI and the CUI 30 W Desktop USB PD Adapter (https://www.digikey.com/short/v0f7fqm2) as the power supply.

Best of all, Digi-Key has tons of CUI 30 W Desktop USB PD Adapters (https://www.digikey.com/short/v0f7fqm2) in stock, the version we're linking to comes with a USA power cable, but they also sell a version without a cable (https://www.digikey.com/en/products/detail/cui-inc./SDI30C-Q-UTB-CUB/16376426) so you can swap out with a UK, EU or other wall plug. Don't forget to also get a high quality CUI USB Type C connector (https://www.digikey.com/short/w23hh4m4) to go with. Order today for immediate shipment!