A quick review of the USB 2.0 standard does not show any EMC requirements for USB power or devices. The USB standard only states that "All USB devices should be designed to meet the applicable regulatory requirements". CISPR 24 should be used to determine acceptable noise and transient levels.
I also would not consider this a new USB concept. There have been USB battery chargers available for some time. I have had a USB cell phone charger for about three years. I see a generalized battery charger as an extension of an existing concept rather than something novel. The most novel application I have seen recently is a rechargeable AA battery. One end is actually a cap that can be removed exposing a USB plug. You can then plug the battery into your computer to recharge it. Once charged, you replace the cap and put the battery back in your battery powered device. No external battery charging cradle is required. The drawback is that the capacity of the battery is significantly diminished because much of the package is devoted to the USB connection and charging circuitry. http://www.usbcell.com/ Ted Eckert American Power Conversion Corporation The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC nor representing APC's official position on any matter. "Price, Ed" <[email protected] om> To Sent by: ieee <[email protected]> [email protected] cc Subject 02/07/2007 07:58 USB Power Converter AM I recently read about a company that will be introducing a series of micro-sized power converters that will attach to a computer's USB port and charge general purpose rechargeable batteries. The logic is that USB ports are ubiquitous, people who have computers typically also have several applications for rechargeable batteries, and the mess of multiple dedicated wall-wart chargers can be eliminated. I realize that this isn't new regulatory territory, but it is a novel use of the USB concept. OTOH, is there anything in the USB definition that addresses RF noise and transients on the USB power bus? Is there a CE/CS USB criteria? Ed Price [email protected] NARTE Certified EMC Engineer & Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military & Avionics EMC Is Our Specialty - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
