Other Parts Discussed in Thread: BQ2063, BQ40Z50
Hi,
We upgraded an existent 3S-2P Li-Ion battery pack based on the old BQ2063 (coupled with an S-8243 protector) with the BQ40Z50-R1.
Our customer uses a charger which interrupts the charging current approximately 1s every 30 seconds to communicate with the battery. This current interruption is necessary to be able to communicate with the battery as SMBus communication lines are multiplexed with the charger power lines in the host system.
During this communication, the charger asks for the battery voltage to adjust its CV setting to compensate for voltage drop in wiring due to 5A charging current. For this compensation to be effective, the battery voltage needs to be measured under current.
The BQ2063 update voltage data every 2-2.2 seconds so the short current interruption have quite no effect on the battery voltage sent by the BQ2063 which is representative of the battery voltage with current.
However the BQ40Z50 updates voltage data more rapidly every 0.25 second so during the current interruption, the voltage sent to the charger is the battery voltage with no current. As this voltage is lower, the CV setting compensation of the chargeris too high leading to overvoltage events.
Old batteries and charger are always used so our customer would like to find a workaround on the new battery to be compatible with the particular operating mode of this charger.
On page 239 of TRM (SLUUBC1D–July 2015–Revised January 2018), the table B-1 shows filter settings with associated time constant but unfortunately, we can't find these settings in the calibration section of the Data Flash parameters so we have several questions :
- Where are these parameters ?
- What is the default value setting currently (supposed to be 10/0.25s) ?
- Is it possible to change these thresholds ?
- Does the modification of these parameters has undesirable effects (if so which ones) ?
Thank you for your support.
Best regards.
Stephane
