BQ40Z50EVM-561: Maximum charge/discharge current limitation

Viraaj Somayajula

Part Number: BQ40Z50EVM-561
Other Parts Discussed in Thread: BQ40Z50

"Charge and discharge current" minimum: 0, typical: 2, maximum: 7A

Hi,

Above SS is from the "bq40z50EVM QuickStart Guide". Why is there a limitation on the maximum charge/discharge current (only 7A. 32A is supported on bq40z50, isn't it? Also protection FETs are 11A rated). As I understand, FW setting OCD register can be used to set the overcurrent trip. What is the maximum OCD amperage possible?

over 5 years ago

0 Andy Liu (BMS) over 5 years ago

TI__Guru 52115 points

We will take a look and get back to you shortly.

Andy

0 Damian Lewis over 5 years ago

TI__Mastermind 34775 points

Hello Viraaj,

The 7A limitation is for BQ40z50EVM PCB design, not BQ40Z50. The current limitations for BQ40Z50 are

15bit plus sign bit current register (~32A)
SRP/SRN Vin max |0.2V|/Rsense value

0 Viraaj Somayajula over 5 years ago in reply to Damian Lewis

Intellectual 295 points

Hi Damian,

Thank you for the response. Do you mean to say that the PCB layout restricts the amperage or is there something in the design as well? Because, as you said register can programmed till 32A and the Rsense used in the design seems to be 0.001 ohm with 1 Watt power rating, which should be good even for 20A. Mosfet rating restrict the current to 11.7A. Is there something else restricting the current?

Regards

0 Damian Lewis over 5 years ago in reply to Viraaj Somayajula

TI__Mastermind 34775 points

Hello Viraaj,

PCB layout continuous current restriction.

0 Viraaj Somayajula over 5 years ago in reply to Damian Lewis

Intellectual 295 points

Thanks Damian for the clarification.

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BQ40Z50EVM-561: Maximum charge/discharge current limitation