BQ40Z50-R1: BQ40Z50-r1

Naveesh Boppana

Part Number: BQ40Z50-R1

Hi,

I am trying to monitor the system Pres on the Fuel Gauge . I was able to find the below information from TRM . Do I need to set any register for this sampling to happen or is it a default gauge setting ?

5.2.1.1 System Present PRES is sampled four times per second, and if PRES is high for 4 samples (one second), the OperationStatus[PRES] flag is cleared. If PRES is low for 4 samples (one second), the OperationStatus [PRES] flag is set, indicating the system is present (the battery is inserted). If the [NR] bit is set, the PRES input is ignored and can be left floating.

I tried monitoring the PRES flag on my battery pack and the flag is always set (Even when there is no system present and I measure the PRES pin which is always low .NR bit is cleared in DA configuration ).Based on the above image the I measure PBI on my battery which is 12.9v . So the PRES pin should stay high until connected to a system , But It is always Low. Can you kindly let me know If there is something we need to set on our end to detect these values properly .

Thanks.

Naveesh

over 6 years ago

0 Onyx Ahiakwo over 6 years ago

TI__Guru* 76230 points

Hi Naveesh
The pres flag is set if your host sets it or if you have the /pres pin pulled to ground. How is your schematic for that pin configured?

thanks
Onyx

0 Naveesh Boppana over 6 years ago in reply to Onyx Ahiakwo

Intellectual 430 points

Hi Onyx,

Please find the schematic attached

Thanks,

Naveesh

0 Onyx Ahiakwo over 6 years ago in reply to Naveesh Boppana

TI__Guru* 76230 points

Naveesh
Where does the pres pin connect to? It ought to be pulled to ground via a 10k resistor.

thanks
Onyx

0 Naveesh Boppana over 6 years ago in reply to Onyx Ahiakwo

Intellectual 430 points

Hi Onyx,

Please find the detailed explanation in the attachment . The PRES pin is always low on our battery pack irrespective of connected to the system or not . Have you seen any similar issue earlier ? I verified our setup with BQ40Z50EVM and everything works normal . It is measured high when not connected to the system around 4V but on the battery pack it is always low.

Thanks,

Naveeshsystem present pin issue 04082019 (002).pptx

0 Onyx Ahiakwo over 6 years ago in reply to Naveesh Boppana

TI__Guru* 76230 points

Naveesh
pls review the schematic of the EVM and your schematic and check to see how the /pres pin connection differs from yours. The fact that the TI EVM doesn't see the issue means something is wrong with your schematic.

thanks
Onyx

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BQ40Z50-R1: BQ40Z50-r1