Russell, Is this the circuit you were referring to in the thread "tiny power supply"? Thanks, Daniel... ----- Original Message ----- From: Russell McMahon To: Sent: Tuesday, August 21, 2001 13:35 Subject: Re: [EE]: Design Challenge - low power step down switching regulator > > Requirement > > > > Step down voltage regulator suitable for powering small low voltage > circuits > > from a higher voltage supply with a reasonable power dissipation. > > > > Overall figure of merit = finished cost while meeting design > specification. > > Costing rules provided below. > ................. > > OK - here's a solution that has been suggested by a friend from the NatSemi > LM336 regulator diode data sheet > > Without going back to my original cost list I estimate that this is about > 130 to 150 units cost. (Under $US1 probably with substitutions below). Not > too bad. > I've pretended that the LM336 here can be substituted with a low cost zener > diode - if not the price is significantly higher. > I've assumed that all transistors can be low cost general purpose ones BC337 > / BC327 as the power level specified in my challenge is low. > Also, the output catch diode could be a 1N4148 ! - not what you would > normally see in this role but again, the power level is low. > > Any improvements on this? > > > > > Russell McMahon > > -- 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