BQ29700EVM-610:

Yogendra Bobra

Prodigy 10 points

Part Number: BQ29700EVM-610

I am testing eval kit for normal operation.

Connected battery 3.6V checked for Dout / Cout and V- signal amplitudes.

Cout is ~3.4V

V- = ~2.8 (supposedly should be close to 0)

and Dout remains low

it seems like it is detecting a load short?

NOT able to figure what is causing Dout to stay low -- I checked everything and all looks normal as expected?

PAck+/Pack- voltage is less than 1 volt and not stable?

I have noted the swap of DOUT and V- on the silk screen for this version and have taken into account for evaluation.

Is it possible to talk to somebody?, I am located in San Jose california.

Thanks,

Yogendra

over 3 years ago

+1 WM5295 over 3 years ago

TI__Guru 54715 points

Hi Yogendra,

The part will go into a current fault mode if PACK- is pulled high enough. See descriptions in the data sheet at https://www.ti.com/document-viewer/BQ2970/datasheet/GUID-7B6D3AF9-AE0B-4F6A-9ED6-AEC0C1152074#TITLE-SLUSBU9SLUSBU94676

It seems you have connected a "cell". Normally the part must be awakened by shorting across the FETs or connecting a charger. Since COUT seems to be on the part is not asleep. Since the cell voltage is "normal", 3.6 V, it should not be in the Over-discharge status. From your description it seems it may be in the Discharge Overcurrent Status. See https://www.ti.com/document-viewer/BQ2970/datasheet/GUID-E750D5B7-C1FD-4034-A071-5B31406CFEA3#TITLE-SLUSBU9SLUSBU95112 The method to get to normal mode would be to connect a charger as described, or momentarily shorting across the FETs in evaluation.

0 Yogendra Bobra over 3 years ago in reply to WM5295

Prodigy 10 points

Thanks -- it solved my problem.

0 Yogendra Bobra over 3 years ago in reply to Yogendra Bobra

Prodigy 10 points

Hi I have one more question -- Does the circuit require a reset, after recovery from detected fault?

The application circuit sometimes stop working because battery voltage@ pack+/Pack- is not correct, after reset the circuit works OK??

Thanks,

Yogendra

0 WM5295 over 3 years ago in reply to Yogendra Bobra

TI__Guru 54715 points

Hi Yogendra,

After fault the BQ297x will need to meet the recovery condition for that fault. There is no reset as such. Recovery conditions are described in the section 9 of the data sheet. Basically they involve manipulating the V- pin by applying a load or charger and the cell voltage adjusting.

0 Yogendra Bobra over 3 years ago in reply to WM5295

Prodigy 10 points

Thanks for clarification -- Yogendra

Power management

Power management forum

BQ29700EVM-610: