Electronics > Projects, Designs, and Technical Stuff
What is "floated" linear voltage regulator?
<< < (8/13) > >>
xavier60:

--- Quote from: 001 on November 21, 2018, 05:57:23 am ---
--- Quote from: xavier60 on November 21, 2018, 05:47:58 am ---Some of us might be talking about different things. "floating type" to me means that the control circuitry has its ground reference connected to the + output terminal rather than the - terminal. The control circuitry floats up and down with the + output  voltage.

--- End quote ---

Yea
This topology  is interesting and new for me
Where I can read about? Some hanbook and classical schematic?

--- End quote ---
You have been asking about this topic for a long time. What is your goal?
I did a search and confirmed that "Floating regulator" is a thing, http://www.circuitstoday.com/floating-regulator
The LM723 is powered from the voltage difference between Vin and Vout. This is not a good idea in practice as the regulator will have a higher than usual dropout voltage.
The important point is that the only connection to the ground symbol is the voltage sense resistor.

001:

--- Quote from: xavier60 on November 21, 2018, 06:35:09 am ---the LM723 is powered from the voltage difference between Vin and Vout. This is not a good idea in practice as the regulator will have a higher than usual dropout voltage.
The important point is that the only connection to the ground symbol is the voltage sense resistor.

--- End quote ---

723 sucks since it didn`t use stabile reference and no way to intelegent current control.
capt bullshot:
If you can read German, here's some schematics and documentation of Heinzinger "Transistornetzteile" (Made in Western Germany  ::):
https://cb.wunderkis.de/wk-pub/heinzinger/

spec:
Just been through this thread. Here is my 2 cents worth.

Floating is a general term which means not connected to a reference point of some sort, normally 0V.

But when it comes to the special use of floating to describe a type of power supply architecture, floating means that the power supply circuitry does not see the full input or output voltage across its terminals. All a floating regulator sees, in essence, is the difference between its input and output voltages.

Examples of floating supplies are practically all three terminal regulators, both positive and negative. For example the ubiquitous LM317 has a maximum allowable voltage of 40V between its input terminal and output terminal. But an LM317 can be made to supply 200V say because it is floating.

In the above case the raw supply might be 220V and, as the output voltage is 200V, the difference between the LM317 input terminal and output terminal is 220V-200V =20V, which is well within the 40V limit of an LM317.

Because the LM317 is a floating supply, its sense terminal is always 1.25 volts more negative than than its output terminal. That 1.25V, which is like an accurate Zener diode, is the voltage reference for the feedback loop that stabilizes the output voltage.

The term floating is really a misnomer, because all voltage regulators are connected, one way or another, to 0V: they must be to function. Having said this, it is possible to have the regulator actually isolated from the 0V line by using an opto isolator for example.

Getting back to the LM317 200V supply, you would connect a 100R resistor between the output and sense terminals and a 15k9 resistor from the sense terminal to 0V. 
001:

--- Quote from: capt bullshot on November 21, 2018, 06:40:15 am ---If you can read German, here's some schematics and documentation of Heinzinger "Transistornetzteile" (Made in Western Germany  ::):
https://cb.wunderkis.de/wk-pub/heinzinger/

--- End quote ---

Awesome link. But all pdfs are unawailable now (It says: "You don't have permission to access /wk-pub/heinzinger/0390 30258 LNG 50-4.pdf on this server."  :blah:)
Can You share it here?
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod