• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 386 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.

TPS40055: Can I use SS/SD pin as enable/disable?

Chase Jeong
Mastermind 7345 points
Part Number: TPS40055

Hello TI Experts,

My customer wants to design with TPS40055, and they want to enable/disable IC using SS/SD pin.

please check the schemes below, which is right or not.

schematic 1 ;

schematic 2 ;

the difference is only the position of tact switch and capacitor.

and we just want to enable the IC when pushing the switch, and disable when release the switch.

please check this simple schematic, and let me know if there are some modifications or better ideas. Thanks.

Best regards,

Chase

  • 0
    TI__Mastermind 33495 points

    Hi Chase,

    the switch should be parallel with the capacitor from SS/SD pin to ground.

    the switch should lock the ON state when push it, this will disable the chip.

    B R
    Andy

  • 0 in reply to Andy Chen
    Mastermind 7345 points

    Hi Andy,

    Thank you for your reply.

    you mean, SS/SD pin to GND without capacitor will disable the chip?

    then if I push the tact switch it will bypass the capacitor and directly connected to GND. right?

    and I have one more question, can I use FET for opposite result? I want to disable the device when I release the tact switch.

    so it should be connected directly to GND when I release the button.

    if I use N-ch FET, I can connect drain and source pin when gate is 0. so the result is opposite.

    but i am now sure about it because drain will connected to SS/SD pin, not power source.

    please check my thinking again. Thanks.

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    TI__Mastermind 33495 points

    Hi Chase,

    You want to disable the device when you release the tact switch (the switch is off state), right?

    the you need to exchange  the position of  R1 and Tact switch !

    B R

    Andy

    .

  • 0 in reply to Andy Chen
    Mastermind 7345 points

    Hi Andy,

    Thank you for your reply. It will be very helpful to my customer.

    Best regards,

    Chase