How to double a regulated voltage - Page 1
Forum section: electronics / beginners

author: Alex30
author_rank: Regular Contributor
timestamp: August 24, 2014, 01:33:01 pm
content: So I was wondering what's the best way to double a regulated voltage of up to 1V? I have a sense signal which goes between 0->1V but I want to be able to double it to throw it on a voltmeter. The only thing is I have been looking at these circuits for doubling voltage but most of them seem to be for an unregulated DC supply. How do I accomplish this with a very clean 0->1V DC range? Oh I also want it to be as accurate as possible

author: WarSim
author_rank: Frequent Contributor
timestamp: August 24, 2014, 02:11:11 pm
content: Quote from: Alex30 on August 24, 2014, 01:33:01 pmIf you have the supply voltages for an op amp available. An op amp based 2x amplifier would be a very common method.Depending on the frequency range a transistor based 2x amplifier would be easy also if you don't need true 0v.Sent from my iPad using Tapatalk

author: IanB
author_rank: Super Contributor
timestamp: August 24, 2014, 02:12:07 pm
content: To increase a smaller voltage to a larger one you use an amplifier.If you want to exactly double it use a precision amplifier with the gain set to 2.This is the job op amps were designed for.

author: Alex30
author_rank: Regular Contributor
timestamp: August 24, 2014, 02:20:22 pm
content: Okay, I was just wondering if there was a cheaper option but looks like no (that is with using some diode and capacitor trickery). Thanks!

author: IanB
author_rank: Super Contributor
timestamp: August 24, 2014, 02:25:07 pm
content: Quote from: Alex30 on August 24, 2014, 02:20:22 pmYou aren't going to get cheaper than an op amp and a few resistors...

author: Alex30
author_rank: Regular Contributor
timestamp: August 24, 2014, 02:36:52 pm
content: Quote from: IanB on August 24, 2014, 02:25:07 pmI suppose so.

author: David Hess
author_rank: Super Contributor
timestamp: August 24, 2014, 07:17:24 pm
content: A charge pump like an LTC1043 can be used as a precision voltage doubler which avoids matched resistors and the errors from operational amplifiers.

author: IanB
author_rank: Super Contributor
timestamp: August 24, 2014, 08:08:15 pm
content: Quote from: David Hess on August 24, 2014, 07:17:24 pmNeat.

author: David Hess
author_rank: Super Contributor
timestamp: August 24, 2014, 08:12:02 pm
content: Quote from: IanB on August 24, 2014, 08:08:15 pmYou can find them used in precision circuits like those found in multimeters with 6 digits or more. An equivalent circuit using a resistive dividers requires matching to within 1 ppm which is a lot more difficult and expensive.

author: Alex30
author_rank: Regular Contributor
timestamp: August 25, 2014, 02:19:12 am
content: Quote from: David Hess on August 24, 2014, 07:17:24 pmExcellent thanks, this is the sort of device I was wondering about. But gee, $9.25 from rs? Will certainly keep this in mind for other projects but for this one I think I will just use an opamp and have a calibration pot. Thanks for the reply!

author: David Hess
author_rank: Super Contributor
timestamp: August 25, 2014, 05:05:37 am
content: Quote from: Alex30 on August 25, 2014, 02:19:12 amThe LTC1043 may be the best of the precision charge pumps for this type of application but it can also be done with general purposes analog switches if you can arrange non-overlapping drive which many have built in. Look for ones with low charge injection.

author: WarSim
author_rank: Frequent Contributor
timestamp: August 25, 2014, 11:21:03 pm
content: Quote from: Alex30 on August 25, 2014, 02:19:12 amYes you got suggestions that will work in most cases, because you did not supply any accuracy specs. Higher the specs required higher the cost. Figure out your requirements and your target budget, then the advice supplied will be more tailored to you needs.Sent from my iPad using Tapatalk