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Constant Current LED driver for "Varying Input Voltage"

I need to design a constant current LED Driver of 1A to drive an LED array (Green) 3 in parallel and 4 in series.
"The input voltage will vary from 16 to 32 and irrespective of this a constant current driver is to be designed.

1.I had tried using linear circuits-LM317,where there was too much heat dissipation (owing to the drop created from "16-32" input).
2.I used a TIP41C transistor and at the base provided a 60mA constant current device(AL5809-60P1-7),to obtain a constant collector current (Ic).However, the current was not constant because of the varying supply voltage,which caused a variation in Hfe cause of variation in Vce.

I have now decided to design an switching circuit.Avoided so far because wanted to avoid EMI issues.
**I'll be glad to receive help/guidance /suggestions as to how to go about with the design of constant current driver with varying input voltage.**
 
A tip31 to offload the linear regulator, and then a resistor.... 60ma? I thought you want 1amp?

Maybe i misunderstood..
 
Replace the constant voltage 12v (sim says 14v) source with an lm317, then vary the voltage

(So your 12 - 30v into the lm317, the 12v out to the tip31)
 

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You can buy a constant current driver with those specs for a few bucks. And it will be switching, so no power dissipation problem.

Bob
 
Replace the constant voltage 12v (sim says 14v) source with an lm317, then vary the voltage

(So your 12 - 30v into the lm317, the 12v out to the tip31)
Thanks.But had already tried that.But power dissipation issues.The remaining drop that happens 20V creates a power dissipation and my LM317 is severely getting heated up.I'am struggling with the design because of the "varying input voltage"
 
No, the lm317 won't heat up, it's offloading the current onto the transistors..

Look at the circuit i designed carefully
 
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