• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 313 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.

TPS61132 Failure

Kevin Corcoran
Prodigy 10 points

I am using a TPS61132PW as shown in Figure 25 of the TPS61132 datasheet. Including all the TI specified components. The only difference is that I have broken the connection between VBAT and the battery with a switch.

What has been happening is that the circuit works great, it outputs 3.3VDC, for a little while. Then, after an unknown and unpredictable amount of time with no wiring changes, the output drops to ~1.3VDC. Following this, again for an an unknown and unpredictable amount of time with no wiring changes, the TPS61132PW gets hot and IC smoke appears.

This has happened roughly 3-4 times. I have rebuilt the circuit thinking it was something I did when I wired it, since I am using wire wrapping wire, but the same result was produced.

What are the possible causes of this? I am wondering whether repeated switching on and off of the switch between the battery and VBAT may be killing the IC. Otherwise I am at a loss. Please help!

  • 0
    TI__Guru**** 166626 points

    These parts do not function well when VBAT is at different potential than the input to the SEPIC power stage, i.e., the inductor.  What may be happening is that when you remove VBAT using the external switch, the internal power FET stays on and eventually damages the FET.  Or, it could be that the other inputs (LBI, EN, SKIPEN, etc) still have a voltage applied to them when VBAT is removed and the ESD cells for these pins get damaged.  If you want to disable the part, either place the switch in front of VBAT and the power stage (i.e., inductor) and the LBI, EN, etc. pins so no input is getting a voltage with VBAT removed OR leave VBAT connected all the time and use EN to turn the output on and off.