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Series Current regulator ? Load and minimum load help

russwr

Dec 20, 2019
15
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Dec 20, 2019
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I need part values for a Series (not shunt) Current Regulator for (28vDC supply) with final 6 amps load with minimum load resistor for 100Ma. Circuit should use MOSFET , and the final 6 A output does go on + off 34% duty cycle. Power supply needs constant small resistor load 100ma to prevent burn out. I can purchase the parts and do the hook up. Needs Zener diode, minimum resistor, Mosfet transistor,
 

Bluejets

Oct 5, 2014
5,996
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5,996
Just about any off the shelf smps would fit.
Linear would need boost output.
 

danadak

Feb 19, 2021
207
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Feb 19, 2021
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A fixed 100 mA current from 28 V could be LM317 :

1661647501450.png

The 6A, is that also a constant current or a varying load when PWM is
in active for 34% ? What is the duty cycle accuracy, same for current
if constant current when active ?


Regards, Dana.
 

Bluejets

Oct 5, 2014
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Used one of those for many years but .......not 6A out of that without some kind of darlington boost transistor.
Even then , whopping great heatsink plus power resistors as well.
 
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danadak

Feb 19, 2021
207
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Feb 19, 2021
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LM317 there just for the min low current requirement, 100 mA, not the 6A.

Thats why the other questions were asked to establish if the 6A when on
is also to be a contact current, that will lead to a solution more like :

1661680659913.png

Or for high efficiency :





Regards, Dana.
 
Last edited:
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