BQ76952: Two BQ7695202 cascade how to connect LD and PACK pin

Star Xu

Part Number: BQ76952

The customer design with 32S battery with two BQ7695202 in series. Currently, the AFE PACK Pin and LD pin on the low side are connected to GND. Actually, the REG1 and REG2 pins of the AFE on the low side have no voltage output, while the AFE PACK pin and LD pin on the high side are connected to B32+. The two pins of REG1 and REG2 on the high side of AFE have voltage output, and the voltage is 5.6V. May I ask whether the AFE PACK and LD pins on the low side should be connected to B16+?

32S battery with two BQ7695202 in series do not use current sampling, only use voltage sampling function,

How to connect LD and PACK when BQ7695202 is not using current collection?

Waiting for your reply.

Thanks

Star

over 1 year ago

0 Max Verboncoeur over 1 year ago

TI__Mastermind 25650 points

Hi Star,

The answer depends on whether the FET configuration is high-side or low-side.

For high-side, see the TIDA-010247 reference design schematic for how we recommend connecting the LD and PACK pins on both devices.

For low-side, see the figure below, take from this application note:

Regards,

Max Verboncoeur

0 Star Xu over 1 year ago in reply to Max Verboncoeur

TI__Genius 9645 points

Hi Max

Thanks for your reply.

AFE does not use current collection, how to connect PACK and LD?

Thanks

Star

0 Max Verboncoeur over 1 year ago in reply to Star Xu

TI__Mastermind 25650 points

Hi Star,

Can you confirm if the FETs are high-side or low-side?

Also, if the FETs are high-side, I recommend reading this application note to provide some more information on high-side stacked configurations.

Regards,

Max Verboncoeur

0 Star Xu over 1 year ago in reply to Max Verboncoeur

TI__Genius 9645 points

Hi Maxwell

Thanks for your reply.

The customer design with 32 series cells and cascaded with two AFEs. Both AFEs only collect voltage and temperature, and do not control charge and discharge MOS and non-charge and discharge current.

So they want to known how to connect PACK and LD?

Waiting for your reply.

Thanks

Star

0 Max Verboncoeur over 1 year ago in reply to Star Xu

TI__Mastermind 25650 points

Hi Star,

If the devices are only for measuring voltage and temperature, then the PACK and LD pins can be connected as show in the diagram below, except for the LD on the lower device, which can be shorted directly to VSS on the lower device.

Regards,

Max Verboncoeur

Power management

Power management forum

BQ76952: Two BQ7695202 cascade how to connect LD and PACK pin