7

Operation description

7.1

Battery charger finite state machine (FSM)

The battery charger implements a CC/CV control algorithm to charge the battery connected to BAT. Since the

STBC15 is dedicated to low capacity batteries pre-charge or termination phases are not necessary. Both the

floating voltage and the charging current are configurable by dedicated pins, VSET1,2 and ISET1,2.

The device finite state machine behavior is shown in following diagram.

Figure 10. Operational simplified state machine diagram

SHM: shelf mode

BPS: system powered by battery

CHG: battery is being recharged, Vout ok

CHG PS: Vout not good, battery charged through M3 body

7.2

Floating voltage selection

The battery floating voltage can be set by VSET0,1 pins. In order to increase the number of charging cycles, lower

floating voltage values are preferred. On the other side, the reduced floating voltage leads to the decreased

energy stored into the battery.

The battery floating voltage can be set by VSET0,1 pins. In order to increase the number of charging cycles, lower

floating voltage values are preferred. On the other side, the reduced floating voltage leads to the decreased

energy stored into the battery. The best trade-off can be chosen according to application needs. Different range of

floating voltages can be utilized by using different part numbers.

STBC15

Operation description

DS12551 - Rev 1

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