Hello,
I have a problem with the BQ2004 when I use the temperature monitoring.
Configuration mode for charge 3 NiMH cells:
TM1 High
TM2 float
VSEL= High
DSEL= High
Fast charge C/2
Fast charge safety time = 180 minutes
PVD Hold-Off Time = 820 s
Top-Off Rate= C/16
Pulse- Trickle Rate = C64
Pulse-Trickle Period (Hz) = 120 Hz
IREG= 0,225/0,25= 0,9A
RB1/RB2= N/2-1= 100K/220K= 0,45
TCO= 1,350V
Thermistore TRMR-MF5A-103J ( 10K with room temperature)
With the TS monitoring there are three working conditions:
1) During the fast charge when VTEMP >1,353V the LED2 is ON.
2) If the temperature increased and 1,329V < VTEMP <1,353V, the LED2 is off and the charge mode is C/16
3) If the temperature increased again and VTEMP< 1,329V the LED2 flashed and the charge mode is C/64
During the charge the problem is the passage from the C/64 to the fast charge mode (batteries inserted on the charger with high temperature), because in the passing of C/16 mode (if the temperature batteries decrease), the charger thinks that the charge is finished and when the battery temperature decreases again so that VTEMP>1,353V, the fast charging will not restart.
In the same way exists the inverse problem when there is the passage from the fast charge mode (VTEMP> 1,353V) to the C/16 mode (1,329V < VTEMP <1,353V) because the charger thinks that the charge is finished and when VTEMP return greater than 1,353V, the fast charging doesn’t occur.
Regards
Mario