• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 21 subscribers
  • Views 167 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.

TPL5010: WAKE Pulse width less than 1ms

Douglas Ross
Prodigy 30 points
Part Number: TPL5010

Tool/software:

Good day, 

We're using the TPl5010 to turn on a mosfet which then powers our circuit. The Wake pin is set to turn on the mosfet every two hours. When the MCU is powered it keeps the mosfet on, we broadcast a BLE package, toggle Done and then switch off the mosfet. 

I have found for some of our units, this works perfectly, but for many others it never wakes again. 

During my testing, I found that the WAKE pin goes high for less than 1ms, which does not give our system sufficient time to start up and we can therefore never send a DONE command. RESET is pulled up to our regulated voltage, so as soon as the power drops, the RESET pin also drops.

From my understanding, the WAKE timer should either reset if you receive a DONE, or if no DONE was implemented and the RESET activated. 

Does RESET not activate because there is no voltage on the 3v3 line? After the initial short WAKE pulse, we do not get another WAKE.

The Schematic below is just for our power circuit. 

Could you please assist in determining why the WAKE pulse is so short?

Regards

Douglas

  • 0
    TI__Guru** 107780 points

    Hi Douglas,

    Can you try remove R16 or use a higher resistance resistor?

  • 0 in reply to Noel Fung
    Prodigy 30 points

    Hi Noel, 

    I removed bypassed R16 and still get the same. 

    I added a capacitor between Q4.1 and Q4.2. This seemed to work, Its giving me a perfect 20ms pulse on WAKE when using a 4.7uF. The issue is however that it then takes too long to switch off. Using 1uF the pulse is 15ms on WAKE. Q4 then switches off a few seconds after NRF_HOLD is released. 
    I've tested in one device that used to not work, I'm going to start testing on more devices. 

  • 0 in reply to Douglas Ross
    TI__Guru** 107780 points

    Hi Douglas,

    You said the uF shunt cap at Q4 pin1 fixes the problem? I cannot understand how it works. The WAKE is a push-pull signal with weak driving capability, that's why I though removing R16 may help.