TPS61032: EN pin does not work

Tomáš Roško

Part Number: TPS61032

Hi everyone,

I have just soldered a new PCB with TPS61032. All seems good, except the TPS61032 not turning off when EN pin is grounded (it is always on, does not matter what is the status of MCU pin (high-low). The EN pin is controlled via N+P MOSFETs from MCU, see the image below:

IN pin is LI-ION battery, BOOST_FET is just MCU pin which outputs 3.3V. The control circuit seems to be working OK, when I pull the MCU pin low, I see no voltage on output of T4. When I pull the MCU pin high, I see there a voltage of battery (IN).

Could anyone please help here?

over 2 years ago

0 Chunjiang Wu over 2 years ago

Prodigy 100 points

put a regisiter to GND on BOOST_EN

0 Tomáš Roško over 2 years ago in reply to Chunjiang Wu

Prodigy 30 points

What do you mean by register? Do you mean resistor?

After looking at the schematic once more, it makes sense to put a pull down resistor between BOOST_EN and GND. Without it the EN pin is just floating (when the MCU pin BOOST_FET is off), which can cause the problems mentioned.

What value would you suggest? 10K is fine?

Thanks!

+1 Bryce Xun over 2 years ago in reply to Tomáš Roško

TI__Mastermind 24320 points

Hi, Tomas,

Thanks for reaching out. As Chunjiang said, when BOOST_FET is low, EN pin will be floating. EN is recommended to connect a 500k-1Mohm resistor to GND.

Thanks.

BRs,

Bryce

0 Tomáš Roško over 2 years ago in reply to Bryce Xun

Prodigy 30 points

Thank you Bryce!

It seems like 10K resistor does the job. I do not care about the current too much as the output will be ON for only a few minutes per hours.

0 Bryce Xun over 2 years ago in reply to Tomáš Roško

TI__Mastermind 24320 points

Hi Tomas,

Thanks for your reply. I'll close this thread now. If you have any questions, you can reopen it or post a new thread. Thanks.

BRs,

Bryce

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TPS61032: EN pin does not work