Using a zener diode as voltage reference with variable voltage regulators - diyAudio
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Old 16th September 2009, 06:25 PM   #1
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Default Using a zener diode as voltage reference with variable voltage regulators

Hi,
I am looking for schematics of regulated power supply where the voltage reference is a zener diode.
More in particular I would like to build a +60V power supply using the TL783.
Is this an insane idea ? will I get low residual ripple ?
Thanks to everyone and kind regards,

ginetto
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Old 16th September 2009, 06:31 PM   #2
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Quote:
Originally Posted by ginetto61 View Post
Hi,
I am looking for schematics of regulated power supply where the voltage reference is a zener diode.
More in particular I would like to build a +60V power supply using the TL783.
Is this an insane idea ? will I get low residual ripple ?
Thanks to everyone and kind regards,

ginetto
Confusing. What is your priority: using a zener, or using the 783, or low ripple (or maybe low impedance?)

jd
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Old 16th September 2009, 06:44 PM   #3
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Originally Posted by janneman View Post
Confusing.
What is your priority: using a zener, or using the 783, or low ripple (or maybe low impedance?)
jd
Thanks for the very kind reply.
Actually my aim is to get low ripple 60V PS with a simple schema because I am a beginner.
it will feed a line preamp eventually
Kind regards,
ginetto
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Old 17th September 2009, 05:51 AM   #4
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Actually I am thinking at a solution like that one attached with the TL783 in place of the tip29
In this way I could go without the RC filters
Is it feasible ?
thanks and regards,
ginetto
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File Type: jpg zenbrde2.jpg (49.1 KB, 304 views)
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Old 17th September 2009, 07:04 AM   #5
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Actually I was thinking about replacing the tip29 with a tl783 in the following schema
http://cygnus.ipal.org/mirror/www.pa...s/zenbrde2.jpg
could it work ?
suggestions are very welcome and appreciated
regards
ginetto
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Old 17th September 2009, 07:51 AM   #6
Elvee is offline Elvee  Belgium
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If you want something simple and effective, the TL783 is certainly the way to go: you just need two additional resistors, and it will amply outclass any simple zener-based regulator.
The ripple rejection will be close to 80dB, meaning that a 6V input ripple will translate into ~1mV at the output.
If you find this insufficient, you may try to bypass the adjustment terminal, although it is not recommended, and requires some precautions.
Alternatively, you may add a gyrator at the input, or use other similar ripple-reduction techniques.
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Old 17th September 2009, 09:38 AM   #7
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Quote:
Originally Posted by ginetto61 View Post
Actually I am thinking at a solution like that one attached with the TL783 in place of the tip29
In this way I could go without the RC filters
Is it feasible ?
thanks and regards,
ginetto
This is not a regulator but just an emitter follower, it has no active regulation. It will always have higher ripple and higher Zout that a real regulator like the 783. There are app examples in the 783 data sheet, that would be your best bet.

jd
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Old 17th September 2009, 10:06 AM   #8
Salas is offline Salas  Greece
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I would not chain 6 Zeners, the normal non compensated parts available to us are very noisy. Use a 6mA Idss Jfet and a 10k 1W resistor for a 60V Vref instead. Will do much, much better.
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Old 17th September 2009, 11:49 AM   #9
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Quote:
Originally Posted by Elvee View Post
If you want something simple and effective, the TL783 is certainly the way to go: you just need two additional resistors, and it will amply outclass any simple zener-based regulator.
The ripple rejection will be close to 80dB, meaning that a 6V input ripple will translate into ~1mV at the output.
If you find this insufficient, you may try to bypass the adjustment terminal, although it is not recommended, and requires some precautions.
Alternatively, you may add a gyrator at the input, or use other similar ripple-reduction techniques.
Thank you so much !
I think that a ripple rejection be close to 80dB is so much more than what I hoped.
Kind regards,
ginetto
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Old 17th September 2009, 11:51 AM   #10
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Quote:
Originally Posted by janneman View Post
This is not a regulator but just an emitter follower, it has no active regulation.
It will always have higher ripple and higher Zout that a real regulator like the 783.
There are app examples in the 783 data sheet, that would be your best bet.
jd
Thank you very much
I will follow your suggestion.
Kind regards,
ginetto
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