Low Cost PCB's Low Cost Components

Author Topic: Bridging Ch2 & Ch3 of the Rigol DP832 to increase 5v current output  (Read 1500 times)

0 Members and 1 Guest are viewing this topic.

Offline ornea

  • Supporter
  • ****
  • Posts: 95
  • Country: au
After much deliberation I was all keen to finally buy a shiny new DP832 and then realised that I am often working on Arcade PCB's where i need 5V @ 4A and 12V @ 300mA

Is it possible to set channel 2 (0 - 30v ch) to 5V and connect in parallel to channel 3 (5v fixed Max 3A) to give the 4A needed.

The manual discusses connecting Ch1 & Ch2 and using tracking mode etc but does not talk about Ch2 & Ch3.

Experimenting would provide an answer in a flash and i cant see why it cant be done.

What say ye.

The DP831 looks perfect with 0 - 8V at 5A but Aussie dealer Emona http://www.emona.com.au/ only stock the DP831A which is out of my price range. Perhaps I should contact them
 
 

Offline bson

  • Supporter
  • ****
  • Posts: 777
  • Country: us
Re: Bridging Ch2 & Ch3 of the Rigol DP832 to increase 5v current output
« Reply #1 on: April 26, 2016, 05:25:09 PM »
No, you can't connect the outputs in parallel.  You'll get current running from one output to the other depending on which happens to be fractionally higher voltage, until it either hits equilibrium or enters CC mode.  In CC mode the outputs will likely bounce around wildly as they take turns entering CC.
<This space intentionally left blank>
 
The following users thanked this post: ornea

Online Marchello

  • Contributor
  • Posts: 18
  • Country: ru
Re: Bridging Ch2 & Ch3 of the Rigol DP832 to increase 5v current output
« Reply #2 on: April 26, 2016, 06:09:03 PM »
Yes, you can connect the outputs in parallel.
I do this often ch1 + ch2 (up to 32V 6.4A with tracking) or ch2 + ch3 (up to 5.2V 6.4A w/o tracking, you need separately set equivalent voltage and current before chan ON)

BR
Mark

Sorry for my english :)
 

Online Ivan7enych

  • Regular Contributor
  • *
  • Posts: 134
  • Country: ru
    • My astronomy projects
Re: Bridging Ch2 & Ch3 of the Rigol DP832 to increase 5v current output
« Reply #3 on: April 26, 2016, 08:50:31 PM »
I would better link channel 1 and 3, to avoid possible ambiguity with current sensor resistors.

In other ways I see no issues.
 

Offline bson

  • Supporter
  • ****
  • Posts: 777
  • Country: us
Re: Bridging Ch2 & Ch3 of the Rigol DP832 to increase 5v current output
« Reply #4 on: April 27, 2016, 03:52:50 AM »
It doesn't matter which channels you try to parallel on the DP832 - it won't do it.  You will have significant cross-currents and voltage drops.  Believe me, I've tried it.  Simply doesn't work.  Get a supply with sufficient output or that can parallel outputs.
<This space intentionally left blank>
 

Offline CustomEngineerer

  • Frequent Contributor
  • **
  • Posts: 344
  • Country: us
Re: Bridging Ch2 & Ch3 of the Rigol DP832 to increase 5v current output
« Reply #5 on: April 27, 2016, 05:07:26 AM »
From page 2-8 of the DP800 Users Guide

    Note:
    1. Only insulated channels can be connected in series or in parallel.
    • For a single power supply, CH1 and CH2/CH3 of DP832 can be connected in series or in parallel, but CH2 and CH3 cannot be connected in series or parallel

    Edit: Formatting fix
« Last Edit: April 27, 2016, 05:09:34 AM by CustomEngineerer »
 

Online Ivan7enych

  • Regular Contributor
  • *
  • Posts: 134
  • Country: ru
    • My astronomy projects
Re: Bridging Ch2 & Ch3 of the Rigol DP832 to increase 5v current output
« Reply #6 on: April 27, 2016, 11:20:34 PM »
It doesn't matter which channels you try to parallel on the DP832 - it won't do it.  You will have significant cross-currents and voltage drops.  Believe me, I've tried it.  Simply doesn't work.  Get a supply with sufficient output or that can parallel outputs.

I can't tell about all power supplies, but Rigol can only source current, it can't sink current if voltage on its output is higher than Vset. So output voltage will be maximum from both channels (when current is low).

In general there can be several cases (assuming both channels are set to 5V, 3A) -

- I < 3A - both channels work in CV mode, output voltage is max from 2 outputs, the channel which have > voltage sources most of the required current.

- I > 3A but < 6A - one channel (which have > voltage) can't keep voltage and works in CC mode, supplying all 3A it can, second channel works in CV mode.

- I = 6A - both channels work in CC mode

 

Offline ornea

  • Supporter
  • ****
  • Posts: 95
  • Country: au
Re: Bridging Ch2 & Ch3 of the Rigol DP832 to increase 5v current output
« Reply #7 on: April 28, 2016, 07:22:45 PM »
So I ordered a DP831 today with Emona.  Begged for a discount and finally when I mentioned that I discovered them via the EEVBLOG, bam, 5% off :-+.  i am happy with that.  Thanks Emona and EEVBLOG
 

Offline Meth

  • Contributor
  • Posts: 12
  • Country: gb
Re: Bridging Ch2 & Ch3 of the Rigol DP832 to increase 5v current output
« Reply #8 on: April 28, 2016, 10:57:14 PM »
Has anyone had any problems bridging Ch1 and Ch2 together?

I'm in the market for a power supply and aside from used Agilents that pop up on the UK auction site (sadly it's not like the US where they crop up ten a penny), I've been considering a new Rigol DP832 (hopefully with discount code too!).
I think for most of what I want to do I won't need to bridge outputs but there are times I might want to run 12V bridged.

Thanks!
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf