Hi,
I'm working on powering a laser diode (1.8 V, up to 9 A) by paralleling multiple LT3081 linear regulators. My plan is to use three LT3081s in parallel to deliver up to 4.5 A (1.5 A per LT3081), and potentially more if needed. I’ve set this up in LTspice, and I’ve attached a screenshot and the simulation for reference (please disregards voltage sources at 0).
In my circuit, I’m using a potentiometer at R4 to adjust the current limit, and another at R11 to set the output voltage.
I have a couple of questions regarding the behavior of these potentiometers: I have read that you can ground the SET pin, so If I remove R4 and R3, will the LT3081 automatically set the output voltage based on the load demand? In my case, the laser operates at 1.8 V - would that voltage be maintained?
Since laser diodes are current-driven devices, how critical is the voltage setting at the SET pin? In the simulation, I set the output voltage to around 1.9 V to prevent overdriving the laser. However, I'm concerned - if I accidentally set the voltage too high (e.g., 3 V), would the LT3081 try to force that voltage and potentially damage the laser? By the way, in the simulation when the SET is to ground, the simulation does not work properly.
I also read in the documentation of the LT3081 that it can be configured as current source, but I am not sure if they can be paralleling or how to achieve it and if thermals will be problematic for the current I would like to get.
Any guidance would be greatly appreciated.
Thanks!
