Post by thread:[OT]: Digitally-controlled variable voltage regula

Hey All, I am trying to construct a powersupply that will be controlled by a pic. I have decided to us the good'ol LM317 as the regulator. I figure that I can use a D/A converter to allow a PIC to control the biasing of a mosfet, used as a variable resistor, to adjust the voltage. Another way I figure is to use a digital potentiometer, only problem is that no greater than 5 volts can be applied to any one pin or pass more than 1 or 2 mA. Anyone got any ideas? Am I making this harder than it should be? How do people like HP do it? (I know HP power-supplies cost an arm and a leg...) I am trying to get 0.1V resolution on the output. James Burkart spam_OUTjamesburkartTakeThisOuTyahoo.com -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam@spam@mitvma.mit.edu

What about using PWM to drive a transistor, create a voltage you can control, and feed that to the ADJ pin? Don't forget a feedback loop! -Randy Glenn Measure twice, cut once, curse, discard. Repeat. ================================================= PICxpertKILLspamcogeco.ca - .....PICxpertKILLspam.....yahoo.com http://picxpert.dyndns.org Not that the site works yet, of course... ================================================= {Original Message removed}

There is complete PWS project in the last ELEKTOR Magazine, using a 16F84 doing all the job, voltage and current indication, setpoints for V and A, RS232, PC-Software, HEX-CODE, Friedel At 02:03 a.m. 22/11/01 -0800, you wrote: {Quote hidden}>Hey All, > > I am trying to construct a powersupply that will be controlled by > a pic. I >have decided to us the good'ol LM317 as the regulator. I figure that I can >use a D/A converter to allow a PIC to control the biasing of a mosfet, used >as a variable resistor, to adjust the voltage. Another way I figure is to >use a digital potentiometer, only problem is that no greater than 5 volts >can be applied to any one pin or pass more than 1 or 2 mA. Anyone got any >ideas? Am I making this harder than it should be? How do people like HP do >it? (I know HP power-supplies cost an arm and a leg...) > > I am trying to get 0.1V resolution on the output. > >James Burkart >EraseMEjamesburkartspam_OUTTakeThisOuTyahoo.com > >-- >http://www.piclist.com hint: To leave the PICList >piclist-unsubscribe-requestspam_OUTmitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList @spam@piclist-unsubscribe-requestKILLspammitvma.mit.edu

What is the ELEKTOR magazine? Is it available in the US? -----Original Message----- From: pic microcontroller discussion list [KILLspamPICLISTKILLspamMITVMA.MIT.EDU]On Behalf Of Friedel Bruening Sent: Thursday, November 22, 2001 11:45 AM To: RemoveMEPICLISTTakeThisOuTMITVMA.MIT.EDU Subject: Re: [OT]: Digitally-controlled variable voltage regulator There is complete PWS project in the last ELEKTOR Magazine, using a 16F84 doing all the job, voltage and current indication, setpoints for V and A, RS232, PC-Software, HEX-CODE, Friedel At 02:03 a.m. 22/11/01 -0800, you wrote: {Quote hidden}>Hey All, > > I am trying to construct a powersupply that will be controlled by > a pic. I >have decided to us the good'ol LM317 as the regulator. I figure that I can >use a D/A converter to allow a PIC to control the biasing of a mosfet, used >as a variable resistor, to adjust the voltage. Another way I figure is to >use a digital potentiometer, only problem is that no greater than 5 volts >can be applied to any one pin or pass more than 1 or 2 mA. Anyone got any >ideas? Am I making this harder than it should be? How do people like HP do >it? (I know HP power-supplies cost an arm and a leg...) > > I am trying to get 0.1V resolution on the output. > >James Burkart >spamBeGonejamesburkartspamBeGoneyahoo.com > >-- >http://www.piclist.com hint: To leave the PICList >TakeThisOuTpiclist-unsubscribe-requestEraseMEspam_OUTmitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

----- Original Message ----- From: "James Burkart" <grafxjkbEraseME.....PACBELL.NET> To: <EraseMEPICLISTMITVMA.MIT.EDU> Sent: Friday, November 23, 2001 7:55 AM Subject: Re: [OT]: Digitally-controlled variable voltage regulator > What is the ELEKTOR magazine? Is it available in the US? > > I believe the US Agents are Old Colony Sound Lab P.O. Box 876 Peterborough NH 03458-0876 Telephone 924 6371 and 924 6526 Fax 924 9467 email RemoveMEcustservEraseMEEraseMEaudioXpress.com Airfreight subscriptions to US are US$80 or US$86 for plus edition which includes CDROM Their web site is http://www.elektor-electronics.co.uk Regards Chris Carr -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 11:55 p.m. 22/11/01 -0800, you wrote: >What is the ELEKTOR magazine? Is it available in the US? It´s a european electronic magazin, pretty good one to, the original is German, there are English and Spanish versions of it. You may look at http://www.elektor.de there you may find the links to the English version Elector and have them sending you a sample. Parts of the project you find at http://www.pic-basic.de. Have fun Friedel >{Original Message removed}

I believe you will find that the original is in Dutch. Elektor themselves produce German, French and English Editions. There are also editions produced under franchise in Sweden, Finland, Greece, India, Poland, Portugal and Spain The Elektor title is owned by Segment b.v. http://www.segment.nl/ Regards Chris Carr ----- Original Message ----- From: "Friedel Bruening" <RemoveMEbolinstspam_OUTKILLspamCOTAS.COM.BO> To: <RemoveMEPICLISTTakeThisOuTspamMITVMA.MIT.EDU> Sent: Friday, November 23, 2001 2:11 PM Subject: Re: [OT]: Digitally-controlled variable voltage regulator At 11:55 p.m. 22/11/01 -0800, you wrote: >What is the ELEKTOR magazine? Is it available in the US? It4s a european electronic magazin, pretty good one to, the original is German, there are English and Spanish versions of it. You may look at http://www.elektor.de there you may find the links to the English version Elector and have them sending you a sample. Parts of the project you find at http://www.pic-basic.de. Have fun Friedel >{Original Message removed}

You don't really need the '317. Use the standard 'series-pass transistor' regulator, except substitute Vref with some form of D/A (low-pass filtered PWM from PIC, or built-in DAC). You will want to add some gain (get a dual op-amp) to get greater output range, of course. Phil Eisermann Electronics Engineer The Ridge Tool Company (440)329-4680 > > {Original Message removed}