Informations about BQ24075 schematics

[Yaro]

Hi all,

I've found some discrepancies between BQ24075 datasheet and crazyflie application.

In schematics I've found that is used 10kOhm resistor for TMR when datasheet specifies min. 18kOhm. This may create some problems? The timer is actually reduced or BQ acts like it have a 18kOhm resistor?

Also, about PM_GOOD and PM_CHG, I've found on datasheet that're adviced two pull-up resistor if this pins are used as logic. But on schematics they are directly connected to MCU. That's correct?

Thank you!

[arnaud]

Hi Yaro,

For the pull-up of PM_GOOD and PM_CHRG they are set in the nRF51 MCU: https://github.com/bitcraze/crazyflie2- ... .c#L58-L61

For the Rtmr I have to look further, it does seems that the safety timer time is reduced.

[tobias]

I think we missed that they specify a min value of 18kOhm. With 10kOhm the safety time will be about 80min and that is 2-3 times the charging time of the 240mAh battery. We have not experienced any problem with the safety timer but if you plan on using bigger batteries it might be a good idea to increase the timer.