lane@cs.dal.ca (John Wright/Dr. Pat Lane) (04/14/90)
What is a "switching" power supply? (ie. what makes it a "switching" type
ass opposed to what? a non-switching power supply?)
They appear to be used in all microcomputers (any exceptions?). How come?
Why exactly is it that you're supposed to wait ~30 sec between switching
off and on again.
Just curious.
PS: please send me a mail copy of anything you post in response to this
as I may miss it as a news article. Thanks.
--
John Wright ////////////////// Phone: 902-424-3805 or 902-424-6527
Post: c/o Dr Pat Lane, Biology Dept, Dalhousie U, Halifax N.S., CANADA B3H-4H8
Cdn/Eannet:lane@cs.dal.cdn Uucp:lane@dalcs.uucp or {uunet watmath}!dalcs!lane
Arpa:lane%dalcs.uucp@uunet.uu.net Internet:lane@cs.dal.cadold@mitisft.Convergent.COM (Clarence Dold) (04/15/90)
in article <1990Apr14.105752.19616@cs.dal.ca>, lane@cs.dal.ca (John Wright/Dr. Pat Lane) says: > > What is a "switching" power supply? (ie. what makes it a "switching" type > ass opposed to what? a non-switching power supply?) A power supply could be as simple as a transformer, with a couple of diodes and maybe a filter on the output. To regulate the output, and maintain a steady voltage, a Linear Supply will be designed so that for any load within its rating, it will be capable of delivering more power than needed. All of the load passes through a regulator, usually a large transistor, which burns off excess power, delivering a stable voltage to the output. There are variables, but on the simplest level, you could say that this power supply will always use the same amount of line power, with some given to the target load, and some burned off wastefully. The switching supply monitors the output target voltage, and switches the input AC on and off at a given frequency, so that the total power delivered is the amount required. In theory, we now have no regulator burning off useless energy, we never take it in in the first place. Plusses: The switching regulator is more efficient at less-than-peak loads. Minus: It is more expensive, and dreadfully more susceptible to power line noise. Linear Supplies usually have gigantic output filters, where the switching regulator has very little filtering, since it can respond faster to a changing load, but the output is very noisy, intolerably so in an environment with poor power. In either of them, the output voltage varies as the load varies, but they both respond to that change in a manner that appears to result in a stable voltage. > Why exactly is it that you're supposed to wait ~30 sec between switching > off and on again. Never heard that one. I think it might be to wait for hard disks to come to a stop, nothing to do with the supply. -- --- Clarence A Dold - dold@tsmiti.Convergent.COM (408) 435-5293 ...pyramid!ctnews!tsmiti!dold FAX (408) 435-3105 P.O.Box 6685, San Jose, CA 95150-6685 MS#10-007