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TPS63020 VINA held low

Terry Garyet
Prodigy 20 points

Other Parts Discussed in Thread: TPS63020

I am using a TPS63020 per the data sheet, with VIN tied to a battery charger, and VINA tied to a .1uf cap and ps_sync.  The input voltage can vary from 4.2V to 2.7V.  The output is @ 5V and about 1A.

If I run until the power (VIN/VINA) is totally shut off because the battery discharges, and then re-apply power (plugging in battery charger circuit), then VIN will go to 4.2V, but VINA only goes to about 0.2V.  Even though EN is high, VOUT is still 0V (presumably because the controller logic isn't properly powered).

I have tried many methods to try to recover:  removing all power, discharging bypass caps, leaving unpowered for an extended time, etc.)  The only way I've found to recover from this is to temporarily short VINA to VIN.After I remove the short, VINA remains at VIN, and everything works properly. 

My conclusion is that the internal logic is in some strange state that draws too much current given the internal resistance between VINA and VIN.  Once enough current is available, the logic finally resets into a low current state and works properly.


I am considering permanently tying VIN to VINA, but I'm worried because don't understand the event that leads to this internal condition.


Do you have any comments or recommendations?  Should I just replace my TPS63020 with another one?

  • 0
    TI__Guru**** 152430 points

    Welcome to the E2E forums.  In order to better support you, please read the guidelines post at the top of this forum.  In particular, please begin the title of your post with the part number.  I have edited your title.

    To debug your circuit, you should especially compare your PCB layout to the datasheet recommendations and EVM implementation.  As well, capture the Vin and Vout voltages on a scope when you reapply your battery.