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TPL5110-Q1: Power saving driving pMOS

Alberto Carlotti
Prodigy 115 points
Part Number: TPL5110-Q1

Hi Team, 

I am considering to use a TPL5110-Q1 for power saving, by enabling the main 5 V supply through a pMOS around every second (tIP–50 ms).

I would connect the DONE pin to ground, and the DRV pin to a nMOS that switches the pMOS ON for around 50 ms and OFF for tIP-50 ms (1 sec).

If possible, I have some questions about the component:

1) May I connect the DONE pin directly to ground? 

2) How much is the max current the push-pull DRV pin can manage safely?  

3) When the DONE pulse is not served the DRV pin goes high after tIP for typ. 50 ms; after this time, dose it turn low again for tIP-50 ms ? looking at fig.8 of the datasheet it could seem it stays high for another time. 

4) May you tell the min and max value of this "50 ms" time? for instance, if it could be as low as 20 ms or as high as 200 ms I have to think to another implementation. On the contrary, if you could confirm it varies within 40-60 ms it would be great.

Thank you in advance for what you can answer

Kind regards,

Alberto Carlotti

  • 0
    TI__Genius 16845 points

    Hi Alberto,

    A1) Yes, that is fine. In this case, DRV would be low for tIP-50ms, and high for 50ms.

    A2) Datasheet specifies VOH and VOL for DRV for 1mA. Would you need more current?

    A3) Your understanding is correct, figure 8 should show the next timer period beginning. That will be updated in a future datasheet revision.

    A4) Based on some data from characterization, the pulse width was consistently 50ms for four units tested for Rext = 500ms

    Kind regards,
    Lane

  • 0 in reply to Lane Boyd
    Prodigy 115 points

    Hi Lane, 

    thank you for your feedback!

    Okay 1mA could be fine. Although, if it would drive up to 2.5mA without any problem, I could think of using the output as the supply for the 50ms pulse. So connecting it directly to the control logic, without pMOS and nMOS. 

    Regarding the 50ms pulse duration sorry, I did not get if you wanted to reassure or not. When our uP has to wake up it takes up to 20-25 ms, so my concern is the pulse should last enough (I would use Rext = 1s) avoiding the risk that it doesn't wake up in time. Do you think there is a good margin to go on, or would you suggest to think about a different strategy?

    Thank you for your support.

    Kind regards

    Alberto

  • 0 in reply to Alberto Carlotti
    TI__Genius 16845 points

    Hi Alberto,

    The 50ms pulse should not have much variation, it should provide sufficient margin. The available data confirms the width would be within 40-60ms.

    Kind regards,
    Lane

  • 0 in reply to Lane Boyd
    Prodigy 115 points

    Hi Lane,

    Okay, thank you for you help!

    Kind regards,
    Alberto