Other Parts Discussed in Thread: BQ24022
Hi,
We have altered the ZVCHG Exit Threshold value from it's default value (2200mV) to 0mv (Zero).
This appears to effectively stop charging from a cell voltage of 970mV all the way down to 0V.
The setup is as follows:
The Cell voltage is simulated by a NGL201 Sink-Source Power Supply
PACK terminals are connected to a BQ24022 which means that 4.2V is applied to the PACK terninals
Cell voltage is then increased in 10mV steps from 0V Up to 970mV and no charging current can be measured
If Cell voltage is instead reduced from 1.10V and down, the charging is still inhibited at 970mV - so it works in both directions
At a cell voltage of 980mV low charge current can be measured - about 10mA
The charge current increase with cell voltage until the cell voltage reaches 1.05V at which the current starts pulsating wih 20ms interval
Another observation:
If the ZVCHG Exit Threshold is set to ex. 500mV then charging is allowed from 0V up to 500mV where it then stops until the cell voltage reach 970mV
There seem to be some crossover zone between 970 - 980mV, any ideas on what happens around 970 - 980mV cell voltage?
Any suggestions on how to prevent charging below 1.30V?
Best regards,
Klaus