10v~60v linear voltage regulator

Discussion in 'The Projects Forum' started by misssty, Sep 15, 2010.

1. misssty Thread Starter New Member

Sep 11, 2010
8
0
hi everybody.
I am working on a control system project. And i need an additonal regulator circuit to regulate my input voltage.

Is it possible to create a linear regulator circuit without using any ICs?
It should be able to handle a wide range of voltage input 10v~60v.

Can anybody give me some suggestions? Many thx.

2. campeck Active Member

Sep 5, 2009
194
3
What output voltage do you need?

edit - OH DANG! I'm a senior member! WOO!

3. Dyslexicbloke Well-Known Member

Sep 4, 2010
546
34
More to the point what current are you looking for, power disipation is likly to be your bigest problem.
Have a look at my recent posts (questions) they are discussing just this issue, amongst others.
Loads of useful input on linear followers and their issues.

Al

4. Ghar Active Member

Mar 8, 2010
655
73
What kind of current do you need?

A linear regulator's power dissipation is approximately (Vin - Vout)*Iload

Since you're saying 10V to 60V I'm assuming your worst case (Vin - Vout) is almost 60V... at 1A you have 60W of heat to dissipate.
Massive heat sink, etc. etc.

You can buy a switching regulator for not very much money and it'll be fairly small and light.

For example here is a module that takes 18 to 72V down to 5V at 1A.

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=102-1848-ND

5. Papabravo Expert

Feb 24, 2006
11,749
2,483
It is possible to create a voltage regulator without using an integrated circuit. It uses transistors, diodes, resistors, capacitors and inductors.

You have specified the input voltage range, but you have said nothing about the output voltage or the output current. Why do you think a design can be produced without that essential information?

Too many fantasy role playing games perhaps?

6. misssty Thread Starter New Member

Sep 11, 2010
8
0
thx for all the replies.
The output is connected to the Vcc input pin of the ATMega8 micro controller chip. Out put should be 5V and the output current should less than 200mA.

7. Kermit2 AAC Fanatic!

Feb 5, 2010
4,166
1,125
A cheap and dirty Zener supply would work for that. Google it up and read all about them. Easy to do and only three components for the simplest of them.

8. Papabravo Expert

Feb 24, 2006
11,749
2,483
So let me get this straight. You're claiming that with 60V on the input and 5V on the output a ZENER would do the job. I don't think so chum!

9. marshallf3 Well-Known Member

Jul 26, 2010
2,358
203
They make huge Zeners if you want to pay for them and the associated resistor, well, winter is coming n North America.

Main questions here are - why do you need to start with 60V? and why are you opposed to using an IC or combination of components that includes one?

10. Papabravo Expert

Feb 24, 2006
11,749
2,483
I suppose being "willing to pay" kinda eliminates "cheap and dirty" as a qualifier for a zener regulator.

(60-5)*.2 = 11 watts means a linear regulator is OOTQ

I think a buck regulator is the only practical solution. Can it be done without using an IC - yes, but WTF would you want to do that?

Last edited: Sep 17, 2010
11. Wendy Moderator

Mar 24, 2008
21,417
2,948

I've said it before, I don't think you can use a MOSFET that way. It is not a valid design.

This will work, but it will get very hot. A heat sink will be required.

The suggestions about using buck boost converters (which are ICs for the most part) is valid. This will get hot due to inefficiencies, a buck boost doesn't get nearly so hot.

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12. misssty Thread Starter New Member

Sep 11, 2010
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thx everyone. I decided to use swithing regulator now. Thx for all teh replies.

13. Kermit2 AAC Fanatic!

Feb 5, 2010
4,166
1,125
Say Papa. Why do you think it HAS to be 60volt going into the Zener.

EVer heard of a resistor divider network? 200mA is all the poster is needing. and that CAN be done easily with a zener.

Do you need someone to draw the circuit?

14. eblc1388 AAC Fanatic!

Nov 28, 2008
1,543
104

It would be interesting to see how it performs at 10V.

15. Kermit2 AAC Fanatic!

Feb 5, 2010
4,166
1,125
You'll need some power resistors and a 5 watt zener, but here it is.

I made the load 33 ohms. The spice program only has a 4.7 volt zener so I used that but the theory is sound and would work. Without wasting more time tweaking to get exactly the 200 mA, this set of values gives 140 something mA to the load at 10V and about 160 something mA at 60 volts.

You guys REALLY needed to see this? I'm disappointed.

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16. eblc1388 AAC Fanatic!

Nov 28, 2008
1,543
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Sort of but you have finally cracked it.

At 60V, the heat in R1 is *only* 120W and adds another 10W for the zener the result is not so bad after all.

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