Ron Fial wrote: > > At 09:14 PM 10/14/99 -0400, you wrote: > >I've looked a little more into the question of recycling ferric chloride > > >Anyone got any ideas on how to efficiently generate 1 A @ 1 V? > >Robert A. LaBudde, PhD, PAS, Dpl. ACAFS e-mail: ral@lcfltd.com > > I assume the key word here is efficiency. > For 1 volt DC output efficiency can be a problem, since most power comes from the wall in the form of AC, and when rectified, there is a 0.7 volt (or more) dr op across standard PN rectifiers. Use a Transformer with a 3-Volt center-tapped secondary, along with Schottky diodes for low voltage drop across the diodes. W ith the center tap arrangement, there is only one diode is in series with the lo ad, versus two if you use a bridge rectifier arrangement. > > Next level: Build a 110VAC to 1V switcher, use 'flat-transformer' technology for 98% or better efficiency. With this type transformer, there is almost zero l eakage inductance, so almost no losses from snubbers, etc. in the primary. On t he secondary, be sure to use Power Mosfets as synchronous rectifiers, so that ON resistance is perhaps .05 Ohms when they conduct and diode losses are virtually non-existent. In other words, you drive the Mosfets on only when the diode the y replace is supposed to conduct. Terrific efficiency. Output voltage or curre nt is easy to control depending on the feedback circuit used. We are talking 98 % efficiency here with 1.0 volts out, scalable to almost any power level. > Regards, > Ron Fial This sounds like a PIC project to me I'd think that PWM switching from a higher voltage power supply would be another possible method, ("Buck switcher") giving about 80-85% efficiency potentially, give the cell phone/CPU industry another 2-3 years & there'll be a Maxim chip or 15 to do this very job, I'd bet. If you wanted to use an off-the-shelf regulator, it would probably take some op amps in the mix to use many existing regulators (as most regulators assume you will "never" need a voltage below 1.35 volts or so), so you'd have a design job potentially there. Mark