BQ20zx gas guage calibration with proprietry software

DAN55143

Other Parts Discussed in Thread: BQ20Z45

HI, I am using a BQ20Z45 that I am flashing and calibrating with my own softare and hardware. I am not using the BQeasy software or EVM. Everything works fine on the device and I have loaded the dataflash with the nescessary values, but I cannot get the device to calibrate. When I enter calibration mode the discharge FET turns off and does not allow me to draw any current. has anyone else experienced this problem? I read somewhere that there were special commands to switch the FETs in calibration mode, but I cannot find what these codes are. I have tried everything I can think of. Has anyone else calibrated the device with custom software? I can manually enable the FETs but as soon as I enter calibration mode by user command 40, the FETS turn off. Thanks

over 15 years ago

0 SW5307 over 15 years ago

TI__Intellectual 825 points

The calibration mode documented in our application note is specifically used in production environment, where the calibration is done on PCB level. The current source is directly applied across the sense resistor, bypassing the MOSFETs.

0 DAN55143 over 15 years ago in reply to SW5307

Prodigy 55 points

Thanks SW. So I run the calibration by applying the current across the sense resistor and bypass the FETs. I asume that I also calibrate the voltage from the battery inputs terminals rather than the pack output terminals. I will give that a go. thanks

0 SW5307 over 15 years ago in reply to DAN55143

TI__Intellectual 825 points

Hi DAN,

As far as the voltage calibration goes, you do not have to calibrate at battery inputs - if there's no load current, it would makes no difference by calibrating at PACK+. Let me know if it works for you.

Thanks!

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BQ20zx gas guage calibration with proprietry software