+/- 5v Regulated Power Supply

Thread Starter

wellyboot

Joined Jun 1, 2005
16
Hi

Im looking for a simple regulated split rail power supply (+5v GND -5v) from a 12-15v DC supply
Its for a low current application <100mA, but the +5v rail will supply more components (ie Pic chip/real time clock/LCD ect) so will have more current flow, the -5v supply only feeding the negative supply rail on a op-amp and a sensor.

I did see a diagram a while back that used a 7805 and 7905 5v regulator ICs, but cant remember where it is!

Thanks
 

Wendy

Joined Mar 24, 2008
21,848
To do what you're wanting the original power supply will have to be floating though, no ground. This is because you want to establish a ground after the fact.
 

weije1986

Joined Apr 19, 2008
14
search the datashet of LM7805 . Inside that datasheet should have information if i not mistaken :)
 

Wendy

Joined Mar 24, 2008
21,848
I have pinouts for several popular chips in my PaintCAD, which you can download off my blog.
 

Tahmid

Joined Jul 2, 2008
344
Hi,
Wellyboot,
This is a common +/- 5v 0.75A power supply. It is cheap and easy to make, but safe to use and very reliable. Hope it will fulfill your requirement. Instead of 100mA, I have given a circuit with 0.75A. If you require less than 100mA, you can use the 78L05 and 79L05 instead of the 7805 and 7905 shown in the schematic. 7805 and 7905 are found in TO220 package and 78L05 and 79L05 are found in TO92 package.


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The strongest man in the world is one, who stands alone for achieving something good.
পৃথিবীতে সেই সবচেয়ে শক্তিশালী ব্যক্তি, যে ভাল কিছু অর্জনের জন্য একাই নিরন্তর চেষ্টা চালিয়ে যায়।
 

Attachments

Tahmid

Joined Jul 2, 2008
344
Hi,
The earlier attachment was a circuit from mains. The one attached here is from 12-15v dc source. It is shown for 1A, but if you require 100mA, you can use 1W zeners.




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The strongest man in the world is one, who stands alone for achieving something good.
পৃথিবীতে সেই সবচেয়ে শক্তিশালী ব্যক্তি, যে ভাল কিছু অর্জনের জন্য একাই নিরন্তর চেষ্টা চালিয়ে যায়।
 

Attachments

Thread Starter

wellyboot

Joined Jun 1, 2005
16
Hi Guys

Thanks very much for the replys so far, havnt had chance to try any of them yet, but will be soon

Thanks again

Dave
 

Wendy

Joined Mar 24, 2008
21,848
It can be iffy, you have to load them down some, but computer power supplies have all those voltages. Being switchers they also have a lot of ripple on them.
 
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