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lm337 negative bias supply. Minimum load?
lm337 negative bias supply. Minimum load?
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Old 12th September 2012, 03:00 AM   #1
bullpeters is offline bullpeters  Australia
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Default lm337 negative bias supply. Minimum load?

I am using a regulated negative bias supply to bias the triodes in a 6sn7 gt for the output stage in a guitar amp. Push pull, both triodes. Basic output stage.
There will probably be around 10mA thru the cathode. Is there going to be a problem getting the LM337 to "switch on" in this instance? There being only a small current thru it. I cant find a minimum current on the data sheet
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Old 12th September 2012, 03:53 AM   #2
wintermute is offline wintermute  Australia
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lm337 negative bias supply. Minimum load?
adjust pin current change is specced at I load >= 10ma (I take it this means that for those specs to be realised the load has to be at least 10ma). The resistive divider normally uses low value resistors that will give the required minimum current.

Something I think it was Jan Didden posted (but I can't remember where) was that a higher load current can be beneficial (up to a point) in stabalising the output. So adding an extra load resistor is not necessarily a bad thing, your reg will just run a bit hotter.

Also have a look at the linear technology datasheet for the 337, it has a lot more detail than the TI/Natsemi one.


edit: found it. it was actually SY that brought it up and Jan expanded on it. http://www.diyaudio.com/forums/power...ml#post1821859
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