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  • TI Thinks Resolved

over current detect and emergency shutdown circuit

Hello sir,

i need to know is there any Evaluation board overcurrent monitoring and overcurrent detected it shut down my input available?

 INA 301 EVM board can only sense over current and it alerts me. but i need to shut down my input when the alert current detected.

is there any EVM board available for current sense with overcurrent detect and shutdown circuit on board?

answer me quickly. I need it very urgent

Regards- Mehul Patel

  • Hello Mehul,

    Can you not connect the ALERT pin to a GPIO pin of the device you want to shut down? What are you trying to shut down? Does it have a shutdown pin? The short answer is that we do not have an EVM where we are actively shutting down some component with a compartator output ALERT pin once an overcurrent condition is detected.

    The idea to these products is that the ALERT pin is based off of digital logic that can control other devices (IC Haus, buck or boost converters, LED drivers) that also possess digital logic input pins. Since the INA301 has an integrated comparator, it can detect over-current condition much more quickly than amplifiers with only an analog output. You can read about these systems here:
    www.ti.com/.../sboa162b.pdf
    www.ti.com/.../sboa168a.pdf
    www.ti.com/.../sboa171b.pdf

    Best,
    Peter Iliya
    Current Sensing Applications
  • Mehul,

    There are some things to note about the INA301:

    - There are two modes of operation: transparent and latched and the mode is set by the RESET pin being pulled low or high respectively.

    - In transparent mode, if the Vsense exceed the threshold set by VLIMIT then, ALERT pin will go low, but will go back up high as soon as the Vsense goes below the threshold voltage.

    - In latched mode, if the Vsense exceeds the threshold voltage, the ALERT pin will go low and stay low even if Vsense goes back under the threshold. To reset the ALERT pin, the RESET pin must be briefly pulsed LOW.

    Attached is a TINA simulation that shows one way to turn off a power supply using the INA300 and two transistors (T1 and T2, which can be both MOSFETs if desired). This would be useful if your the power source you're shutting down does not have a shutdown pin. This design also shows how it is necessay to operate the INA301/INA300 in the Latched mode, or else the system would go back and forth between ALERT high and low if what your are shutting down is what you are measuring as well. The INA301 does not have the RESET pin modeled, but the INA300 does have this ability modeled so I am using it for demonstrative purposes. The only difference is with the INA300 you set the mode (transparent of latched) using the LATCH pin. You also reset the ALERT output using the LATCH pin on the INA300 as well.

    LGVC_OCP.TSC

    Sincerely,

    Peter Iliya

  • In reply to Peter Iliya:

    ok sir, thnks.

    my connections on INA301 board.

    just check is it ok or not?

    vcc= 5v , gnd=ground, 50 mili ohm resistor SMD type in between IN+ and IN-.( from supply side IN+ and from load side IN-)

    jumper J1 on pin 2 to 3 for transparent mode and jumper j2 for alert enable.

    there are some another soldered like pins named ALERT, RESET, AND VS , VOUT all is used for???

    why are these pins given on board? 

  • In reply to mehul patel:

    Mehul,

    Connections are good for normal operation. The soldered pins ALERT, RESET, VS, VOUT allow you to interact easily with the INA301 pins. The functions of these pins can be seen in the datasheet.

    Peter Iliya

    Current Sensing Applications

  • In reply to Peter Iliya:

    yes sir,but i want t o know is this pins are internally connected ?  

    or i have to connect it to anywhere externally?

    which pin connections i have to do to operate this Evaluation board?

    is it  

    VCC

    Vout

    Gnd

    In+, IN-

    all of these pins i already have connected? then i cant understand what is the problem.

  • In reply to mehul patel:

    Mehul,

    I assume you are referring to the problem in your other thread here:

    Please review my suggestions in the other post. If you are still experiencing problem please reply back with:

    - What are your connections for your INA301EVM.

    - Do you have a measurement of the load current?

    - What is the R3 (threshold-setting resistor) value for your INA301EVM. This needs to be changed if you want a threshold of something other than of 2.528V.

    Sincerely,

    Peter Iliya

    Current Sense Applications

  • In reply to Peter Iliya:

    heloo good morning sir,

    my r3 for EVM is 31.6 Kohm . i want to measure max 500 mili ampere current . for 500 mA current i have used shunt resistor 50 mili ohm. but my problem is why my current is not passed through the circuit?

    i have already done the experiment it works well before. but now it is not working.

  • In reply to mehul patel:

    Mehul,
    I'm not sure I understand what you mean by "my current is not passed through the circuit." Do you mean that current from the bus line through the shunt resistor is not reaching the load? Or do you mean the voltage generated across the shunt resistor isn't being amplified and driven on Vout? Perhaps you can share some of the debugging steps you have taken?

    Best Regards,

    Jason Bridgmon, TI Sensing Products Applications Support

    Current Shunt Monitor Video Training Series

    Hall Effect Sensor Video Training Series

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.

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