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Megahertz
- 25th August 2011, 16:39
Can anyone please advise any widely available fixed voltage regulator to take input voltage between 40-60V and output 24V or 12V? Thanks

gadelhas
- 25th August 2011, 16:45
Can anyone please advise any widely available fixed voltage regulator to take input voltage between 40-60V and output 24V or 12V? Thanks

Hi;

The Input/Output Voltage Differential of the LM338 is about 40V, so see if it will be able to work in your project.

Megahertz
- 25th August 2011, 16:54
What is the MAX Input Voltage in this regulator? I am sorry, I am not so good in reading and understanding datasheets

gadelhas
- 25th August 2011, 17:16
From the datasheet;
"Since the regulator is “floating” and sees only the input-to-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not exceeded,"

sayzer
- 25th August 2011, 18:49
Lm2576hv-12 : 0.5a ≤ iload ≤ 3a : 15v ≤ vin ≤ 60v
lm2576hv-15 : 0.5a ≤ iload ≤ 3a : 18v ≤ vin ≤ 60v
lm2576hv-adj : 0.5a ≤ iload ≤ 3a : 4v ≤ vin ≤ 60v

Charles Linquis
- 5th October 2011, 04:03
You can always pre-regulate. Just use an NPN transistor that has a Vce that is 150% of your input voltage, and put two resistors across the device. One from GND to Base, the other from Collector to Base. Choose resistors that give a current flow of about 5% of the output current. Connect the Emitter to the input of your regulator. Put a small capacitor (1uF) on the input of the regulator to GND.
If you choose your resistors properly, you can drop as much or as little voltage across the transistor as you wish. Now you can use a 20V max regulator, if that is what you have.
The transistor and resistors will, of course dissiplate some power and should be sized accordingly.

Dave
- 5th October 2011, 12:21
Charles, Just exactly what I was thinking... PreRegulator.... Megahertz, Just search the internet with the keyword preregulator and see what you find.

Demon
- 22nd January 2012, 04:50
Moved from Schematics.

Robert