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Digital potentiometer for soft start of LASER diode

Nidhi Singh
Intellectual 390 points
Other Parts Discussed in Thread: LM134

Hi,

I am powering my LASER diode using  a constant current source (LM134) in which the output current is set using a set resistor. I want to soft start (gradually increase current from threshold to optimum)the LASER diode by gradually decreasing set resistance value.

Can I do this using a digital potentiometer as set resistance of the current source? 

If yes, the set resistance value should be in the range of 150 ohms to 30 ohms with a step size of 1 ohms, which is the suitable digital potentiometer for such an application?

Regards,

Nidhi Singh

  • 0
    TI__Expert 5140 points

    Hi Nidhi,

    I'm moving this to the Linear regulator forum to verify if a DPOT can be used with LM134. If it's possible I would suggest using TPL0401 as this is a DPOT with a single potentiometer. However, you may not be able to get the step size/resolution you want (30ohm to 150 ohm). Here is part of the table of the resistance values that shows this:



    Thanks,
    Siby