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TPS61032 Device Enable pin (EN) grounded but still there is output voltage

John Samathanam
Prodigy 20 points
Other Parts Discussed in Thread: TPS61032

Hi,

I would like to turn off the output voltage by grounding the EN pin of TPS61032. But even after grounding the EN pin there is about 3V appear on VOUT.

(SYNC pin is grounded.). I like to completely turn off the output voltage.

Thanks

John

on datasheet

"It is put into a shutdown mode when EN is set to GND. In shutdown mode, the regulator stops switching, all internal control circuitry including the low-battery comparator is switched off, and the load is isolated from the input"

 

 

 

  • 0
    TI__Mastermind 46905 points

    hi John

    what is the input voltage in your application? is there other rout that powers the output? please try to apply a small load to the VOUT to discharge the capacitor

    thanks

    Jasper Li

  • 0 in reply to Jasper Li
    Prodigy 20 points

    Thanks Jasper,

    Input voltage is from a Li battery 3.7V. There no other outputs feeding the TPS61032 output. I have attached the block diagram of my circuit.

    Without the USB, just powering from battery, if I ground the EN line I still see about +3V on the output. (same with USB plugged in).

    (RX TX from FTDI/uC  has been removed)

  • 0 in reply to John Samathanam
    TI__Mastermind 46905 points
    hi John
    use a power supply to replace the battery input.
    1. connect a 50ohm resistor to +5V when EN=L, observe VOUT voltage.
    2. EN=H, and add 500mA to +5V, capture the SW and VOUT waveform.(if the device normally operating)
    3. remove the TPS61032, and observe the VOUT voltage
    4. solder a new TPS61032 to the board and re-try step 1 and 2
    5. if the same phenomenon can be found in other board?

    thanks
    Jasper Li