On Monday, July 29, 2013 20:29:54 Chris Knadle wrote: ... > I've been meaning to study a common computer switching power supply to try > to figure out the underlying topology. They're likely "buck converter" > type, but I haven't verified that.
I found a few links about computer switching power supplies that describe the theory and operation, along with some schematics of some actual ATX power supplies. There are apparently some additional standards when it comes to computer power supplies concerning reducing harmonics introduced back into the input line voltage as well as efficiency, and that leads to some interesting circitry added to the input section of the supply, such as PFC (Power Factor Correction) as well as EMI (ElectroMagnetic Interference) filtering. http://www.smps.us/power-supply.html http://www.smps.us/computer-power-supply.html http://www.smpspowersupply.com/power-supply.html http://www.smpspowersupply.com/atx-power-supply.html#bridge Another interesting thing I've deduced from observation is that some ATX supplies switch at different rates in various load conditions. I have a friend that has a supply that is electronically oscillating such that as it's turned off there's loud audible whine that lowers in frequency, and at steady- state when the supply is "off" (ATX supplies are never fully off) the whine is quite annoying. [For the time being the owner has decided to live with the noise rather than replace the supply.] -- Chris -- Chris Knadle [email protected] _______________________________________________ Mid-Hudson Valley Linux Users Group http://mhvlug.org http://mhvlug.org/cgi-bin/mailman/listinfo/mhvlug Upcoming Meetings (6pm - 8pm) Vassar College Aug 7 - Scripting Your World with Python Sep 4 - NoSQL and MongoDB Oct 2 - OpenFlow: Open Standard for Networking Hardware
