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TPS25940AQRVC Hotplug

AGXIN
Intellectual 510 points

Hi 

I am using the protection switch in one of our design  The following are the values calculated for our device constrain 

The i/p voltage for the device is from the battery 12 V

RLIM_CALC 32.96296296 KΩ
R3 37.4 KΩ
R2 10 KΩ
R1 487 KΩ
VOV 14.14588235 V
VUV 11.16151899 V
FAST TRIP 4.425 A
VIMON 4.65437037 <6
RIMON 33.11965812 KΩ
IINRUSH 1.642935378 A
VPGTH 11.24808511 V
R4 487 KΩ
R5 47 KΩ

When the battery is hot plugged the switch is not providing the output voltage (It Is capable of supplying up to 2 A@12v)

we have changed the value of DV/DT from 2200pF to 10pF but there is no change the same behavior is observed .

How to fix the problem with hotplug ?

 

  • 0
    TI__Guru** 105361 points
    Hi AGXIN,

    Thanks for reaching out!.
    Please let me know the load details (Rout, Cout) and share the waveforms of Vout, Iin, Vin at the moment of hotplug with dVdT capacitor 2200pF.

    Thanks and Regards,
    Rakesh
  • 0 in reply to Rakesh
    Intellectual 510 points

    hi 

    I will share the wave forms with voltage probes at the point mentioned 

    we are having the captive load at the time of start up in our board 

    the 12V output is connected to the 337 UF capacitive load placed at the i/p side of DC dc converter the same 12 V is directly given to a SOM module from tegra 

    we dont have any information regarding the module but the module is also having dc dc converter so 100-200uF may be present at the module 

    so a total of 500uF  (Cout) is Present and we dont have any Resistive load in the board at the 12V side we have changed the values of the capacitor from 2200PF

    to 10PF all are having similar response  

    schematics 

  • 0 in reply to AGXIN
    TI__Guru** 105361 points
    Hi AGXIN,

    Can you also check EN pin voltage. Looks like EN threshold is just on the max. threshold. Use 20k for R187.
    Since load capacitance is 500uF. I suggest to use >3.3nF at dVdT pin.
    Please test and revert back if you still have issue.

    Regards,
    Rakesh