STBC21 Datasheet, PDF (15/54 Pages) STMicroelectronics – LI+ battery charger with thermal regulation

STBC21
Detailed description
5.2
Battery connection detection
The STBC21 includes a battery detection algorithm to avoid a wrong behavior of the charger
due to incorrect pin connection. This control is performed both at the beginning and at the
end of charge.
At the beginning of charge, the charger briefly (T_DETECT) sources a small current (I_DETECT)
to the battery: if the voltage remains below V_RECH, the battery is definitely connected.
Otherwise, if the voltage reaches V_RECH, a further control is added to be sure the battery is
not connected. The charger briefly sinks (T_SINK) a small current (I_SINK) from the battery. If
voltage falls below V_{PRE_CH}, the battery is certainly absent.
Similarly, when the termination current is reached, the charger briefly (T_SINK) sinks a small
current (I_SINK) from the battery. After this period, if the battery voltage is above V_{PRE_CH}, the
battery is present. Otherwise the battery is absent. The flowcharts in Figure 5 better explain
this algorithm.
Doc ID 023256 Rev 1
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