BQ34Z100 Current offset calibration

Slim123

Hi,

Based on experiment, we are unable to perform current calibration when there is no current flowing. If the chip is reading current when actual current flow = 0A, is there a way for us to calibrate this current offset while the chip is in idle state (without charge and discharge)?

Thanks.

over 10 years ago

0 ThomasCosby over 10 years ago

TI__Guru 73830 points

No, the gauge requires a charge or discharge current to calibrate the current gain. The CC Offset and Board Offset currents are calibrated when no current is present.

0 Slim123 over 10 years ago in reply to ThomasCosby

Expert 1210 points

Hi Tom,

Thanks for the prompt reply. I have tried to do CC offset and board offset calibration manually when no current present but it does not calibrate the current offset away. The current reading is still there. To correct this we must calibrate the current gain with charge or discharge current?

0 ThomasCosby over 10 years ago in reply to Slim123

TI__Guru 73830 points

The current gain calibration will not zero out a current reading that is caused by an offset or noise issue. Are you using the TI EVM or a custom PCB?

0 Slim123 over 10 years ago in reply to ThomasCosby

Expert 1210 points

Hi Tom,

Its a custom PCB.

0 ThomasCosby over 10 years ago in reply to Slim123

TI__Guru 73830 points

Is the current sense filter circuit located very close to the device with the traced place parallel to one another from the sense resistor to the device? You could also try shorting across the SRN and SRP pins to see if you can zero the current. This could provide a clue as to whether there is a layout issue that is introducing an offset.

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BQ34Z100 Current offset calibration