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.**
"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.**