What is an "offline regulator" / TIP150 ?

Discussion in 'General Electronics Chat' started by DMahalko, Jun 22, 2012.

  1. DMahalko

    Thread Starter Active Member

    Oct 5, 2008
    174
    14
    While looking for a high-current 125v DC voltage regulator, there's a TI application note for an "offline regulator" circuit.

    This isn't relevant to my research project, but I can not find any explanation for what this term means on Google, maybe someone can clarify?

    Should there be an "offline regulator" wikipedia article to fill the knowledge gap?

    TI application PDF for the TL783 high voltage adjustable regulator:
    http://focus.ti.com/lit/ds/symlink/tl783.pdf


    Figure 18, page 10. 125-V Short-Circuit-Protected Off-Line Regulator



    (I will add the circuit image from the PDF later. Photobucket is down for maintenance at the moment.)
     
  2. #12

    Expert

    Nov 30, 2010
    16,257
    6,755
    In the USA, the 120 VAC power line, when rectified, yields about 170 VDC. The circuit in the datasheet shows how to use this chip if you use the rectified voltage OFF the power LINE.

    Somehow I don't think that warrants the publication of an intellectual dissertation but, I might be wrong.
     
  3. DMahalko

    Thread Starter Active Member

    Oct 5, 2008
    174
    14
    Your response does not make any sense to me.

    To rewrite this, do you mean:

    "The circuit in the datasheet shows how to use this chip if you use 120v RMS AC through a bridge rectifier as input DIRECTLY FROM THE POWER LINE."


    Or do you mean something else? I associate "off-line" with battery backup systems and I don't see any potential meaning there.
     
  4. #12

    Expert

    Nov 30, 2010
    16,257
    6,755
    Yes, I mean exactly what you wrote. Under the heading, "High Voltage Regulator", getting voltage off the power line means the same thing as getting voltage from the power line. It doesn't mean anything about the status of the digital processing system any more than charging a battery means a bunch of men attacking a row of cannons :D.

    ps, here's the datasheet you referenced.
     
    Last edited: Jun 22, 2012
  5. DMahalko

    Thread Starter Active Member

    Oct 5, 2008
    174
    14
  6. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    Taking a look at DC/DC converter also on Wikipedia I see the information for typical switching frequency: 300 kHz to 10 MHz.

    I have built some dc/dc converters myself and I don't think there is a lower limit of 300 kHz.

    What leads to the idea the author or the authors have not build many dc/dc converters if any.
     
  7. DMahalko

    Thread Starter Active Member

    Oct 5, 2008
    174
    14
    Wikipedia articles are often written by non-experts such as myself.

    If you have more intimate knowledge of a subject matter and can cite your edits so they can survive review by non-experts, then please go ahead.
     
  8. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    It's a bit scary as if SMPS frequencies to be used are defined by the fact if this can be prooven to exist in literature.

    While in reality SMPS frequency can often be adjusted freely, and is set as required.

    I do however lack the correct skills to edit wikipedia. Information needs to be formatted to meet the various rules and style guides, not so much reality out there. If I would edit towards to represent reality as close as possible (given the fact I have knowledge about the topic), then very likely it will become reverted and/or attacked, and experience has shown, by more regular/more bureaucratic editors, who don't neccessarily know anything about the subject!

    In reality it only matters to me to get along with the technology, get the circuit working, save costs, and to produce a result! Grammar, university, literature reference are totally secondary to me.

    But yes I know, wikipedia is not a how-to guide (for instance).

    Would it be a helping if I give the information I have built maybe 50 different dc/dc and/or SMPS circuits? I don't count myself as expert, but certainly I have some experience/knowledge about the topic (or area of related topics).
     
    KJ6EAD likes this.
  9. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Source: http://www.smps.us/smps-glossary.html

    Note that this forum does not support discussion of transformer-less power supplies; the supply must be isolated from mains power by a transformer, whether low (line) frequency or high (switching) frequency.

    The advantage of higher frequency switching is the much smaller size transformer core that is required.
     
    KJ6EAD and Wendy like this.
  10. takao21203

    Distinguished Member

    Apr 28, 2012
    3,577
    463
    You can see such a PCB in the attach:

    Line voltage rectifier (left),
    Control IC (Off line SMPS),
    Isolating flyback transformer,
    Feedback optocoupler,
    secondary side rectifiers/filters (right).
     
  11. DMahalko

    Thread Starter Active Member

    Oct 5, 2008
    174
    14
    SgtWookie:

    I assume the intent is so that the novices on this forum who don't understand nominal RMS AC utility voltage don't electrocute themselves thinking their unfused unisolated "low voltage" circuit doesn't pose a shock hazard.

    But rule compliance is as easy as using a commercial isolation transformer on the front end of whatever is being discussed.

    Google shopping: isolation transformer
    http://www.google.com/search?q=isolation+transformer&tbm=shop
     
  12. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Beginners all too frequently want to avoid the expense/weight/bulk of galvanic isolation via the use of a transformer. They don't realize that a transformer is a great deal more affordable than a funeral.

    The problem here is that a beginner would likely think that the isolation transformer could simply be omitted to save cost/space/weight. They simply are not aware of the grave hazard they would create by omitting the isolation.

    So, we simply don't discuss that type of thing, as we don't want to give beginners bad ideas. While the primary topics on here are electronics & electricity, safety is the overriding concern. We want our neophytes to enjoy their new hobby safely.
     
  13. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,535
    Wookie is telling you straight, this is indeed AAC policy. The moderators here frequently lock threads because of that violation. If you look at the bottom of the page you will see a link to the ToS, or Terms of Service, where these policies are spelled out in great detail.
     
Loading...