Hytera TC-700, Service Manual, Page: 44 / 50

Description of TC-700 Desktop Charger
58
Charge Termination
1. Maximum Charge Time (NiCd, NiMH, and Li-Ion)
The bq2000T sets the maximum charge-time through pin RC. With the proper selection of external
resistor and capacitor, various time-out values may be achieved. Figure
Ⅱ shows a typical
connection.
Figure
Ⅱ
Typical Connection for the RC Input
2. Maximum Temperature (NiCd, NiMH, and Li-Ion)
During fast charge, the bq2000T compares the battery temperature to an internal high-temperature
cutoff threshold, V
TCO
. As shown in Figure
Ⅲ
, high-temperature termination occurs when voltage
at pin TS is less than this threshold.
Figure
Ⅲ
Temperature Monitoring Configuration
3. Peak Voltage Detection (Ni-Cd, Ni-MH battery) (PVD)
bq2000T adopts PVD method to stop the charging of Ni-Cd and Ni-MH batteries. It continuously
samples the voltage of BAT pin which reflects the voltage of the whole battery. Bq2000T begins
PVD function if this voltage is less than the maximum sampling voltage 3.8mv (PVD). As shown in
Fig. IV, the resistor-divider between the anode of the battery clip and Vss pin determines the
voltage of BAT pin.