What about the opposite? From 1.5V or 3V to 5V? I know there are several IC doing that but here in Brazil it's not that easy to get them. Friendly Regards Octavio Nogueira =================================================== nogueira@propic2.com ICQ# 19841898 ProPic tools - low cost PIC programmer and emulator http://www.propic2.com =================================================== ----- Original Message ----- From: "Roman Black" To: Sent: Wednesday, September 05, 2001 11:28 AM Subject: Re: [EE:] 1 transistor SMPS circuit !!!!!!!! :-) > Edson Brusque wrote: > > > > Hello Roman and Russell, > > > > > Here's the first 2-tran SMPS regulator: > > > http://centauri.ezy.net.au/~fastvid/smps02.gif > > > > I've built this on a protoboard and it seens to work. I don't have the > > correct inductor on hand, but tried with 3x220uH=660uH and it's oscilating > > at about 100kHz. Also, I've put a 5.1V zenes as I don't have any 5.6V. I'll > > try to buy some 1.5mH and 5V6 tomorrow to test it. > > > > What output current does you spect to source with this circuit? > > > Hi Edson, I got 100mA to 120mA with OK efficiency > even with the little RF choke. > > Any larger inductors were better, especially <1.5uH > values, I got 200mA with good efficiency out of some > of them. > > Do you have a cro? It's very easy to tune the efficiency > if you can see the waveform at the collector of Q1. > -Roman > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.