bq20z80 - current used for charge termination

NBA

Other Parts Discussed in Thread: BQ20Z80

Hello,

The bq20z80 ref manual states that the "Average Charge Current" must be < Taper Current value for 2 consecutive Current Taper Windows, etc. etc. to terminate charging.

My question is, what is the "Average Charge Current" used for this part of the termination test? Is it the same as the "AverageCurrent" value (the 1-minute rolling avg)? Or is there less averaging used on the current value checked for termination? If so, how much averaging / filtering is done on this particular current?

Thanks,
NB

over 12 years ago

0 ThomasCosby over 12 years ago

TI__Guru 73830 points

The AverageChargeCurrent is a 14.5s rolling average of the current. this is the current that must drop below the Taper Current threshold.

Regards
Tom

0 NBA over 12 years ago in reply to ThomasCosby

Prodigy 110 points

Thanks Tom.

As a follow-up, how many samples are used for that 14.5s avg? Or alternatively, what's the sample rate?... (I'd like to do some simulations to make sure any noise coming from my charger won't interfere with the termination sequence.)

0 ThomasCosby over 12 years ago in reply to NBA

TI__Guru 73830 points

Current is sampled every 250ms and these are averaged over a 1 second period and reported as the SBS Current. This 1 second current data is input into the 14.5 second rolling IIR filter for the average current value.

Regards

Tom

Power management

Power management forum

bq20z80 - current used for charge termination