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Current Monitor and Overcurrent protection in mA Current range

Nidhi Singh
Intellectual 390 points
Other Parts Discussed in Thread: LM134, INA301, INA300

Hi.

I am driving a LASER diode using a constant current source (LM134) where I am setting the output current using a resistor. I have observed that sometimes the current shoots up above the set current value. I want to monitor current to the  LASER diode and also need an overcurrent protection provision.

The current range in which my LASER diode functions is 1-3mA. Can you suggest a product for this application?

Regards,

Nidhi Singh

  • 0
    TI__Genius 15760 points

    Hi Nidhi,

    Thanks for considering TI products. You can take a look at INA300 or INA301. 

  • 0 in reply to Mayrim Verdejo
    Intellectual 390 points
    Dear Mayrim,

    If im using INA301A3 for current sensing and over current protection and I want to keep cutoff current as 2mA, then I would be setting comparator trip point as 2mA * 10mohms = 20uV. This would get multiplied by the gain 20uV*100v/v and I get 2mV. For this I need to put R3 as 25ohms.

    So my first question here is :
    Is it possible to keep comparator trip voltage as small as 2mV?

    My second question is what is the significance of full scale sense input voltage? What does it indicate?

    My last question is, datasheet says that input voltage at J4 terminal is the differential voltage referenced to ground. Does it mean that on Vin+ i have to give 0-36V and keep Vin- at ground?

    Regards,
    Nidhi Singh