120VDC Supply from 13.8Vdc
in [Design]
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From: Jacques St-Pierre on 28 Jul 2008 17:12 Anyone can suggest a simple way to design/build a switching supply to produce 120Vdc at 2 or 3 amps from a 13.8Vdc (car battery) with of the shelves parts? I thought using a cheap inverter and rectified the output, but the one I test produce a 150Vpp square pulse, witch will result in a 150Vdc output. A bit too high for my application. They do not appear to be adjustable to reduce output to 120Vpp. Bye Jacques St-Pierre
From: mrdarrett on 28 Jul 2008 17:31 On Jul 28, 2:12 pm, "Jacques St-Pierre" <multe...(a)globetrotter.net> wrote: > Anyone can suggest a simple way to design/build a switching supply to > produce 120Vdc at 2 or 3 amps from a 13.8Vdc (car battery) with of the > shelves parts? > > I thought using a cheap inverter and rectified the output, but the one I > test produce a 150Vpp square pulse, witch will result in a 150Vdc output. A > bit too high for my application. They do not appear to be adjustable to > reduce output to 120Vpp. > > Bye > > Jacques St-Pierre Dangerous, but... give these a try http://sound.westhost.com/project69.htm
From: mrdarrett on 28 Jul 2008 17:32 On Jul 28, 2:12 pm, "Jacques St-Pierre" <multe...(a)globetrotter.net> wrote: > Anyone can suggest a simple way to design/build a switching supply to > produce 120Vdc at 2 or 3 amps from a 13.8Vdc (car battery) with of the > shelves parts? > > I thought using a cheap inverter and rectified the output, but the one I > test produce a 150Vpp square pulse, witch will result in a 150Vdc output. A > bit too high for my application. They do not appear to be adjustable to > reduce output to 120Vpp. > > Bye > > Jacques St-Pierre yes, "these" (sorry, my finger slipped) http://sound.westhost.com/project69.htm http://sound.westhost.com/project89.htm "Seriously though, the risk of severe burns and the possibility of causing a fire in your car are very real, and should not be underestimated. 300A from a car battery can do a vast amount of damage in a few milliseconds - should the fuse not blow (you will use a fuse, won't you?), then the damage can be extensive." Enjoy Michael
From: Joerg on 28 Jul 2008 18:17 Jacques St-Pierre wrote: > Anyone can suggest a simple way to design/build a switching supply to > produce 120Vdc at 2 or 3 amps from a 13.8Vdc (car battery) with of the > shelves parts? > > I thought using a cheap inverter and rectified the output, but the one I > test produce a 150Vpp square pulse, witch will result in a 150Vdc output. A > bit too high for my application. They do not appear to be adjustable to > reduce output to 120Vpp. > I guess you meant 150Vp, not Vpp (that would be 300Vpp). To make that work you'd have to take a few windings off the secondary of the big ferrite transformer in there until you get to 120VDC. Instead of rectifying it's more efficient to disable and bypass the bridge that creates the usual "fake" 3-step AC. Results in a little more efficiency. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Tim Williams on 29 Jul 2008 02:45
"Jacques St-Pierre" <multelec(a)globetrotter.net> wrote in message news:6Dqjk.2256$%b7.2132(a)edtnps82... > I thought using a cheap inverter and rectified the output, but the one I > test produce a 150Vpp square pulse, witch will result in a 150Vdc output. > A bit too high for my application. They do not appear to be adjustable to > reduce output to 120Vpp. Bah, trace the control circuit, they usually use a TL494. Find the feedback resistors and insert trimmer. Caveat: they're sensitive to turns ratio because the DC is cap-input filtered. :-x Adding a choke after the rectifier would be a nice thing to do for the MOSFETs. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms |