MC33772 Coulomb Counting CC_OVR_FLT

[MarcelloArca]

According to datasheet of MC33772 the Coulomb counting related fault FAULT3_STATUS[CC_OVR_FLT] is set in case of overflow on the Coulomb counter, i.e. if accumulator is higher than threshold set by register TH_COULOMB_CNT_MSB and TH_COULOMB_CNT_LSB.

I would like to kwow if overflow occurs only with positive currents, or also in case of negative ones, i.e. with negative value of accumulator COULOMB_CNT, i.e. violation of threshold is performed based on absolute value of accumulator?

[MarcelloArca]

Thanks for the reply.

It seems that the case you are referring is for the overflow on the entire range of the accumulator, which sets CC_P_OVF and CC_N_OVF.

I am referring to the bit ADC2_OFFSET_COMP[CC_OVT], which should be set when "the coulomb counter crosses the threshold
TH_COULOMB_CNT, which is specific to Sleep mode and produces the setting of both
ADC2_OFFSET_COMP[CC_OVT] and FAULT3_STATUS[CC_OVR_FLT] bits." (page 41 of the RM rev.3).

I would like to use the threshold TH_COULOMB_CNT to wakeup the AFE from sleep in case of low discharging or charging currents for a sufgficiently long time, i.e when some Ah flow on the cells, but from tests I have performed the bit seems to be set only for positive counter (charging). Can you confirm if this is the case or it is possible to set the fault bit both for positive and negative counts?

[JozefKozon]

Dear Marcello,

I need to contact an application team for an advice. They always require following details. Could you please provide? Especially the Annual Volume.

Customer: ARCA TECNOLOGIE SRL

End Customer: ? (can also be ARCA TECNOLOGIE SRL)

End Application: ?

Country: Italy

Annual Volume: ?

With Best Regards,

Jozef

[JozefKozon]

Dear Marcello,

yes, its affected by both, positive and negative overflow. 

With Best Regards,

Jozef