One day project - 0-300 VDC adjustable power supply - Page 1
Forum section: electronics / projects

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: December 10, 2011, 03:04:25 pm
content: Well sometimes i need a small power supply going up to 300 VDC for tests. Commercial power supplies in this voltage range are quite expensive and not easily available.Since i tough this might be useful i decided to share it.However i did not need anything fancy and decided to build one. First at the drawing board i made a SMPS with TL494, H-bridge feeding a transformer but i had some switching problems which made my gate driver IC-s die. Since i did not have anymore gate drive IC-s i decided to make something much simpler...After about half of hour on the test board i came to a very simple and reliable design. The eagle schematics and board files are attached (this is not optimized board, i just used auto route to make it as quick as possible, this power supply PCB does not need any special design, however you can optimize it to better suit your flavor).All parts are recycled except the fuse holder.The maximal output voltage is approximately 330 VDC and minimal is around 1/4 VDC. The mosfet does not requite heatsink. The circuit is self explanatory, and feel free to ask any questionsWARNING - > ALTROUGH THIS POWERSUPPLY INPUT VOLTAGE IS 220 VAC DO NOT USE MAINS VOLTAGE TO POWER IT. IM USING A 12-220 VAC INVERTER AND IF YOU WILL POWER IT FROM LINE USE A SMALL ISOLATION TRANSFORMER. TRYING TO POWER THIS FROM THE GRID WILL KILL YOU!!!

author: Lightages
author_rank: Unknown
timestamp: December 12, 2011, 12:04:02 am
content: Thank you for sharing this. One question, what do I open your files with?

author: Chet T16
author_rank: Frequent Contributor
timestamp: December 12, 2011, 12:42:54 am
content: For some unknown reason i decided to wipe my computer today and install windows 7 so i can't check but the original post says they're eagle files

author: IanB
author_rank: Super Contributor
timestamp: December 12, 2011, 01:02:12 am
content: You know, if someone doesn't post a circuit diagram as a plain picture (Dave CAD even), I'm not interested.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: December 12, 2011, 01:12:17 am
content: Harcklordspiner, what is the brand and model of your variable power supply ? ( I think is a switching variable power supply ).

author: Lightages
author_rank: Unknown
timestamp: December 12, 2011, 04:17:54 am
content: Quote from: Chet T16 on December 12, 2011, 12:42:54 amOf course if I read a bit more.....

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 12, 2011, 05:03:26 am
content: i think this is a normal linear power supply. Vac is feed to a full bridge rectifier, then a big decoupler cap and then a regulator. direct from mains possible, wont kill unless you touch ityes i wonder what regulator model that can take up to 330V input. i like this kind of design though... KISS principle, not a kind of that complicated "69" kind of feedback loop power supply.

author: metalphreak
author_rank: Frequent Contributor
timestamp: December 12, 2011, 06:57:12 am
content: IanB: for your eyes only :p

author: Psi
author_rank: Super Contributor
timestamp: December 12, 2011, 07:07:21 am
content: hehe, unlike a conventional power supply with a ramp-up and maybe a little overshoot.This thing looks like it would have a ramp-*down* from 300V when a load is connectedAt least there's no output capacitorAs i understand it, the fet is being used in between its on and off states, so like a variable resistor.With the pot setting the fets "resistance" and therefor the output voltage (given the load resistance)The 2nd transistor provides some current limiting to shut off the fet if the current gets too high.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: December 12, 2011, 09:26:20 am
content: Quote from: IanB on December 12, 2011, 01:02:12 amSomebody allready posted a jpg image, im just used to eagle and dont bother to export the schematics in any other formet ( i will do it next time)Quote from: DavidDLC on December 12, 2011, 01:12:17 amWhich one, there is about 6 of them (the SMPS ones). If its about that 4 in front of the circuit it goes like this :Bottom is Voltcraft VSP2653HE (SMPS, guts herehttp://www.hacklordsniper.com/Slike_projekata/Projekt_(1)/Voltcraft/Slika%20(2).JPGTop there are 2 programable, SMPS supplies, unknown manufacturer (guts herehttp://www.hacklordsniper.com/Arhiva_projekata/Projekt_(14).htmlAnd on top right is the Atten APS3005s

author: DavidDLC
author_rank: Frequent Contributor
timestamp: December 17, 2011, 12:43:28 am
content: Quote from: hacklordsniper on December 12, 2011, 09:26:20 amLinks don't work

author: Unknown
author_rank: Unknown
timestamp: December 17, 2011, 12:45:34 am
content: Just remove the closing bracket on the end.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: December 17, 2011, 03:48:29 pm
content: Quote from: alm on December 17, 2011, 12:45:34 amThank you. I fixed the original links