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LT3080 High Voltage Floating Regulator
LT3080 High Voltage Floating Regulator
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Old 6th January 2018, 02:03 AM   #61
jackinnj is offline jackinnj  United States
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LT3080 High Voltage Floating Regulator
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Originally Posted by DualTriode View Post
“Reverse-PSRR” addresses disturbances caused on the load side of the regulator.
Yes, probably relates to the inadequacies of the error amplifier. The concept was probably developed by the folks in Austria who make the Bode-100, or their co-conspirators at Sandler Associates (Picotest.com)
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Old 6th January 2018, 01:52 PM   #62
jackinnj is offline jackinnj  United States
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LT3080 High Voltage Floating Regulator
Here's the application note: https://www.omicron-lab.com/fileadmi...nsfer_V2_0.pdf
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Old 8th January 2018, 07:15 AM   #63
DualTriode is online now DualTriode  United States
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Default Pretty clever,

jackinnj,

Thanks for the insights and link to more expensive test/measurement equipment. I think of it as load regulation. Omicron Lab calls it Power Supply Reverse Transfer. I will follow your lead and call it Reverse PSRR.

Pretty clever that Jung/Didden Regulator with the boot-strap connection to the pre-regulator ADJ pin. Load side disruptions wrapped around for the pre-regulator to modulate as if the disruptions were on the line side.

DT
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Old 8th January 2018, 07:32 AM   #64
SSassen is offline SSassen  Netherlands
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@Jack,

That looks like a nice piece of kit, but well outside of anyone's hobby budget if they're just looking to get some PSRR or reverse PSRR measurements done. Besides, any hobbyist worth their salt will come up with a way to do just that, albeit not with the click of a button, it'll involve noting values in a Excel sheet with a function generator being sweeped across a frequency band.
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Old 8th January 2018, 11:47 PM   #65
DualTriode is online now DualTriode  United States
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Hello,

just ordered a Jensen transformer to use per this AP Application Note 106.

https://www.ap.com/download/technote...I-4UsmuWQQgc7Y

Looks straight forward to use with APx555.

Not to reinvent the wheel but to get the tools up and functioning.

DT

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To download this AP TN106 you first need to login to the AP site.
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Old 11th January 2018, 11:35 PM   #66
tomchr is offline tomchr  Canada
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In the past, I've injected current for phase margin measurements using a Tektronix CT-6. At $600 it's not exactly cheap. Then again, if you do need to measure the PM, it's pretty handy to have.

As pointed out in the AP tech note, beware of transformer saturation with DC current when measuring PSRR, line rejection, and the like.

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Not to reinvent the wheel but to get the tools up and functioning.
That's my philosophy as well.

Tom
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Last edited by tomchr; 11th January 2018 at 11:38 PM.
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Old 12th January 2018, 01:42 AM   #67
jackinnj is offline jackinnj  United States
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LT3080 High Voltage Floating Regulator
The transformer mentioned in the AP Application note is pretty good -- but only to 22kHz.

Having a 2-way conversation w Elvee on this topic.
What we need for testing HV tube supplies

An VNA can be set up as an S-parameter test set without a lot of hassle.

Injecting current galvanically (via CT6)-- I think the operative frequency range should be 10kHz to 10MHz -- that's where the problems seem to surface. You'll need a "normalize" regimen on your VNA to deal with the probe's issues below 250kHz.

Last edited by jackinnj; 12th January 2018 at 01:48 AM.
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Old 15th February 2018, 04:39 PM   #68
Ioannis66 is offline Ioannis66
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I 'd like to ask if the Schema Power supply variable IRFI840 posted earlier in this thread can work as a variable power supply of 50-250 volt at a max 400mA current.

Also, the internal current limiting of the 3080 is enough to protect it in case of a short circuit at the output?

My next step would be to find a way to digitally control the output voltage. Maybe in the place of the pot a current source controlled by a MCU can be used.
Thanks,
Ioannis
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Old 15th February 2018, 08:14 PM   #69
jackinnj is offline jackinnj  United States
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LT3080 High Voltage Floating Regulator
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Originally Posted by Ioannis66 View Post
My next step would be to find a way to digitally control the output voltage. Maybe in the place of the pot a current source controlled by a MCU can be used.
Thanks,
Ioannis
The voltage at the top of the current setting resistor is going to be close to the output voltage.
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Old 16th February 2018, 09:50 AM   #70
Ioannis66 is offline Ioannis66
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Yes I understand that. For this reason I though a current controlled way to replace the pot.

My main concern is how to protect the 3080 in case of a short circuit as the chip will "see" the full input voltage. Also the 400mA current I want at the output.
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