bq20z45 v 1.05 will not shutdown with command current is less than zero

HI Ken,

Try to have your guage report zero current when you actually have zero current. Did you hit the CC board offset calibration button under the pack voltage and CC boad offset calibration section? Also try calibrating your pack current by bypasasing the fets, i,e checking the FET control off field and the connecting a current source accross the sense resistor (pack - and 1N).

Then make sure the condition for shut down as stated in the trm is met during normal operation.

thanks

Onyx

Have done multiple passes at the CC cal.  Sometimes the current is shown 0, sometimes it is -3mA.  But even if there is a -100mA draw, the current in discharge is always less than zero.  We should be able to shutdown during a discharge according to the documentation of the command.

We can increase the current deadband to give a zero current and then the shutdown command works.  But the docs say the shutdown should work in discharge.  Is this wrong?

the current has to be zero. Ps see trm, pg 46.

thanks

Onyx

Yes, but in Appendix A, pg 53 of the same document (pg51 in the March 2011 revision) it says the Shutdown Command instructs the part to enter shutdown when pack voltage < charger present and current is less than or equal to zero.

Ken

I would say you hold the info on page 46 as the correct one. I Tested the command with a discharge current through my packs and shut down mode was not entered. Thanks

Onyx