Post by thread:looking for components/advices

Hi everyone! I have a couple (or few couples?) of problems. How to begin... So, in one my application I need a kind of voltage source switch. Let me explain, I'm putting up a circuit (controlled by a PIC, obviously) that have to operate from the telephone line, when active, and automatically switch to battery power if the line fails or the circuit is in standby mode. All this have to be VERY low power, so that the battery do not discharge too fast (few months min.). I intendend to use a voltage comparator(s) to do this, then the problem of reference voltage come up. I tried to use a zenner, but it draws too much current for stabile operation. I found some voltage reference circuits, but they need too much current/voltage to work properly. Can I trust the battery for a stabile voltage? Has anybody any suggestion regarding voltage references (low power 50uW?) or, better, about a "supply controller"? The entire circuit is working at 3.0-3.3V and draws 6mA max. when functioning and about 25uA when in stand by. Thanx in advance, Mauricio CULIBRK ARNE Computers d.o.o. Cesta v Gorice 38 Phone: +386 61 1233-171 61111 Ljubljana Fax: +386 61 1233-488 Slovenia E-Mail: spam_OUTmauricioTakeThisOuTarne.si E U R O P E

Hi there, I was a few days off, so maybe that response is already to late... > > "supply controller"? The entire circuit is working at 3.0-3.3V and draws > 6mA max. when functioning and about 25uA when in stand by. In genral you should check MAXIM products for that purpose. They make alot of stuff for handhelds and so an. I would recommend you the MAX872. It takes 10uA from the supply and operates down to 2,7V. Henri -- =============> The sanest place is still behind the trigger <=============== []-------------------------------[]---------------------------------------[] || Henri Schultze || Magdeburg D-39122 Alt-Fermersleben 88 || || .....henriKILLspam@spam@fscz-md.boerde.de || The Cracker Company || []-------------------------------[]---------------------------------------[] =================> in a world of compromise, some don't <=================== some dance to remember, some dance to forget