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LP2901-Q1: Is it possible to use as over current protection, current sense comparator?

NY
Expert 3040 points
Part Number: LP2901-Q1
Other Parts Discussed in Thread: TPL7407LA-Q1, , TLV1701

Hi team,

My customer is thinking to develop automotive interior LED lamp, multiple LED shall be used in this application.

I would like to promote TPL7407LA-Q1, which is low side LED driver but do not have current protection. 

Customer requires current protection, since low side LED driver, need sensing at high side with multi channel comparator.

I am thinking LP2901-Q1 will be good, but I would like to confirm if this is really used as high side current sensing comparator.

Please let me know. 

Regards, NY

  • 0
    TI__Guru 52346 points

    Hello Naoki,

    Are you high-side sensing at the battery voltage? Or the LED drive voltage?

    The LP2901-Q1 is not a rail-to-rail input, so the comparator input voltages must be between GND and 2V below the comparator V+ supply voltage.

    You would need a rail-to-rail input device, such as the TLV1701, to do high-side sensing.

    Keep in mind the comparator offset voltage can be positive or negative (±9mV). So if you are planning to just measure a few millivolts across a low value sense resistor, there is a good chance the output could "stick" due to opposite polarity offset voltage. You will need to calculate with both a +9mV and -9mV comparator offset voltage.

  • 0 in reply to Paul Grohe
    TI__Expert 3040 points
    Hi, thank you very much!