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INA180: current sense for current limit application

zevi kramer35
Prodigy 50 points

Part Number: INA180
Other Parts Discussed in Thread: INA181, INA301, INA300

we intend to use the INA180 to sense the current on the high side.

one of the uses is to measure the current during a short and when the current goes beyond a threshold -> Turn a mosfet OFF.

the load is capacitive + resistive.

the voltage is a 12V lead acid battery 12-14.5v

we supply 3.3v to the chip.

questions:

1. are there any protections we need to put on the input for this application?

2. we expect the chip to respond within 5usec. would it work? if not, what is realistically the delay?

thank you!

  • 0
    TI__Expert 4915 points
    Hi Zevi,

    The INA181 has a slew rate of 2V/uS and a minimun delay assuming no input filtering.
    Therefore the response time will vary according to the required output. In any case it will always be better than 2uS.

    There should be no requirement for input protection unless you're dealing with 'load dump' transients, for example cutting back power to an inductive load, in which case protection is required (also valid for the mosfet and other devices sharing the same supply.)

    Finally, I also find it worth to mention we have two other devices (the INA300 and INA301) which are specifically built for such purpose, having a built in latching comparator with hysteresis already integrated.
  • 0 in reply to Carlos Silva85
    Prodigy 50 points
    got it carlos. we are looking at the INA181/INA130