Author Topic: Suggestion: Bipolar power supplies  (Read 2372 times)

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Offline colorado.rob

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Suggestion: Bipolar power supplies
« on: November 30, 2018, 03:58:02 am »
Dave, I been interested in getting a bipolar power supply for a bit but I realize I know very little about how they work and what they are typically used for.  They seem like a power supply and DC load in  one.  How does their design differ from these instruments? Can you do a video to enlighten me?
« Last Edit: December 01, 2018, 04:30:40 pm by colorado.rob »
 

Offline Brumby

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Re: Suggestion: Bipolar power supplies
« Reply #1 on: November 30, 2018, 04:43:35 am »
You're after the functional operation of a four quadrant power supply.

Dave mentions this in this video - but doesn't go into the detail that you're after
 

Online thm_w

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Re: Suggestion: Bipolar power supplies
« Reply #2 on: November 30, 2018, 09:13:46 pm »
OP is also likely thinking about a two quadrant supply, often used for testing batteries or mobile devices. Also called dynamic dc source, or battery simulator/analyzer sometimes.

For example 66312A: https://www.keysight.com/en/pd-1000001616%3Aepsg%3Apro-pn-66312A/40-watt-dynamic-measurement-dc-source-20v-2a?cc=CA&lc=eng
NGMO1: https://www.rohde-schwarz.com/us/product/ngmo1-productstartpage_63493-9512.html

Generally a lot less expensive than a four quadrant SMU.
 

Offline alm

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Re: Suggestion: Bipolar power supplies
« Reply #3 on: November 30, 2018, 10:20:33 pm »
Dave did a teardown of such a two quadrant battery simulator that can both source and sink current. Not that much attention to the theory of operations, unfortunately:


If you look in the service manual of instruments like the HP/Agilent 66312A or the older HP 6825A, you'll find a description of the theory of operations, block diagrams and (simplified) schematics.
 

Offline colorado.rob

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Re: Suggestion: Bipolar power supplies
« Reply #4 on: December 01, 2018, 05:08:42 pm »
Thanks guys.  My needs are for battery simulation to test both batteries and charging circuits.  The instruments I am looking at are the Keithley 2281S and ITech IT6432.  The Keithley has the brand recognition.  The ITech is less expensive, can sink more current, which might be important to me, and has two channels.  The Keithley is a two-quadrant PS (1.5 quadrant given that it can't sink as much as it can source?), but the ITech appears to be a four-quadrant supply.

I had to do a lot of research to discover that this is what I needed and thought that a "Fundamentals Friday" style video would be enlightening.  The tear-down videos are interesting and educational, but they don't really go into details about what they are, how they work, when you might need one, and the proper way to use them.
 

Offline Kean

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Re: Suggestion: Bipolar power supplies
« Reply #5 on: February 18, 2019, 02:33:35 pm »
The instruments I am looking at are the Keithley 2281S and ITech IT6432.

Did you end up going with either of these?
I'm in a similar situation of deciding between a Keithley 2281S and an Itech IT6411.  I have a limited budget, and not 100% sure either will give a sufficient ROI.
 

Offline colorado.rob

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Re: Suggestion: Bipolar power supplies
« Reply #6 on: February 23, 2019, 03:37:18 am »
Did you end up going with either of these?
I'm in a similar situation of deciding between a Keithley 2281S and an Itech IT6411.  I have a limited budget, and not 100% sure either will give a sufficient ROI.
No, not yet.  I was just looking again today.  I think I can get by with the programmable power supply I have and a programmable electronic load.  I'm waiting to see what the Siglent DC load looks like.  If I do need such an instrument, I'm pretty much set on the Keithley.

And, unfortunately, after watching Shahriar's SMU videos, I now really want a 4-quadrant device (or three!).
 

Offline schmitt trigger

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Re: Suggestion: Bipolar power supplies
« Reply #7 on: April 10, 2019, 04:09:07 am »
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