On Jun 18, 2007, at 11:33 AM, Randall Nortman wrote: > On Mon, Jun 18, 2007 at 10:46:31AM -0700, Steven Michalske wrote: >> Putting a LC filter on the output of the bridge rectifier will help >> you out. > > I looked briefly at LC filters to handle 120Hz ripple. Requires some > pretty large, expensive inductors if I'm not mistaken. Seems cheaper > in both board space and money to have more capacitance. >
toroidial inductors work best here. you don't need full filtering here, i'll go dig up some old papers i have on this and get back to you laters > >> Be careful with over sizing switching power supplies, what is the >> minimum operating current of your design? > > My understanding is that with low currents that switcher will enter > discontinuous mode (where inductor current goes to zero at the end of > each cycle), and this will cause higher output ripple at the switching > frequency and more overshoot on the voltage. This is not a big > problem in my application. Is there something else that I need to be > aware of? Make sure the switching regulator is designed for it > > I haven't calculated minimum current, but I'm guessing 50mA. (Peak is > around 350mA, designing for 1.5A. so that's a big range.) > > > _______________________________________________ > geda-user mailing list > [email protected] > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
