• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 34 subscribers
  • Views 325 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TRS3232E-Q1: Current consumption

Alex Teryohin
Prodigy 115 points
Part Number: TRS3232E-Q1

Tool/software:

Hello all,

I have a following scheme:

I have 130ohm resistor at VCC input to protect supply in case of VCC short to GND.

According to a datasheet the current consumption is:

However I measure about 3V at VCC. Resistors's voltage drop is 2V, hence current is about 15mA.

Test conditions are slightly different.

Am I missing something?

I can replace 130ohm resistor by jumper, but I would like to understand the cause of higher current consumption.

Sincerely,

Alex.

  • +1
    Guru 317090 points

    During power up, the current consumption is higher because the charge pump needs to charge the output capacitors. It's possible that the power-up state never ends because of the supply voltage drop.

    You should indeed remove R200.

  • +1
    TI__Guru 73331 points

    Hi Alex,

    As far as I know, none of our devices are designed with a large series resistor between Vcc and the power rail. As Clemens pointed out, you can see higher supply current spikes during power up since a lot of the circuitry inside needs to become biased. You may be putting the device in an unknown state where it can't complete it's power up because it's not getting enough current. I suspect the switching regulator may be struggling as well since the current is being limited to the switching caps. 

    For potential shorts, you may be able to design protection using a fuse directly in front of your power tree. 

    -Bobby

  • 0
    Prodigy 115 points

    Clemens and Bobby thanks a lot!

    Do you know if TI has checked this start-up current and what this current pulse duration is?

    Should it be tens of milliampers current?

    Sincerely,

    Alex 

  • 0 in reply to Alex Teryohin
    TI__Guru 73331 points

    Hi Alex,

    Unfortunately not. We normally take DC char data on datasheet parameters, not transient unless it's specifically called out in the datasheet parameters.

    -Bobby