BQ2970: BQ29700 query

Star Xu

Genius 9645 points

Part Number: BQ2970

My customer design the schematic follow the EMV.

The CELL terminal is connected to a 3.3V lithium battery without connecting the load and charging circuit,

the Dout is only 0V, the Cout port is 2.48V, and V- is 2.78V.

It is not same to the normal working state timing diagram Not the same, very close to over discharge.

Thanks

Star

over 5 years ago

0 WM5295 over 5 years ago

TI__Guru 54715 points

Hi Star,

See the caution in the data sheet normal mode after battery connection. https://www.ti.com/document-viewer/BQ2970/datasheet/normal-operation-slusbu95139#SLUSBU95139

When connected DOUT will be low. As the part is pulling up V- to maintain low current mode, V- should measure the highest voltage in the system. See the Over-Discharge Status section of the data sheet https://www.ti.com/document-viewer/BQ2970/datasheet/over-discharge-status-slusbu99520#SLUSBU99520. The meter resistance will pull down on measurement of V-, PACK, or COUT to reduce the voltage below the idle voltage. Something needs to pull the V- more than 1.3V below BAT to wake the part.

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BQ2970: BQ29700 query