BQ27421 average current

Ben Siegfried97

I'm having an issue measuring average current with the BQ27421 gas gauge IC. It will sometimes give the correct value (8-10mA for my system), but for long stretches it will output 0mA, which is obviously incorrect. Sometimes it will randomly jump back to the correct values after a little bit, other times I need to reset the device.

I thought the IC automatically entering sleep mode might have been the cause so I disabled sleep mode in the OpConfig register, but that had no effect. Reading battery voltage and state of charge always give the right values, so I know I'm talking to the IC correctly.

Has anyone seen this before, and is there a fix?

Thanks,

Ben

over 9 years ago

0 Samuel Allen over 9 years ago

TI__Prodigy 370 points

Hi Ben,

Did you make sure to calibrate the board offset correctly? An incorrect board offset could cause issues at such low currents.

Sam

0 Ben Siegfried97 over 9 years ago in reply to Samuel Allen

Prodigy 20 points

Hi Sam,

No, I haven't tried that. This isn't a fixed offset, its more like an either/or problem. But its worth a shot.

Are you referring to setting the "Board Offset" variable ("Data" subclass, offset 0)? The technical reference doesn't give much information about it. Is there a calibration procedure?

Thanks,
Ben

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BQ27421 average current