Operation description

STBC03

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DocID029927 Rev 2

8

Operation description

The STBC03 is a power management IC integrating a battery charger with an embedded

power path function, a 150 mA low quiescent LDO, two SPDT load switches and a

protection circuit module (PCM) to prevent the battery from being damaged.

When powered off from a single-cell Li-Ion or Li-Poly battery, and after having performed all

the safety checks, the STBC03 starts charging the battery using a constant-current and

constant-voltage algorithm.

The embedded power path allows simultaneously the battery to be charged and the overall

system to be supplied.

By contrast, when the input voltage is above the valid range, the battery supplies the LDO

as well as every load connected to SYS.

The STBC03 also protects the battery in case of:



Overcharge



Over-discharge



Charge overcurrent



Discharge overcurrent

CHG pin starts toggling, signaling the fault.

life of the end-product during its shelf life.

8.1

Power-on

When the STBC03 is in shutdown mode, any load connected to LDO and to SYS is not

supplied.

presence of a battery or if the battery is fully depleted, allows the loads connected to SYS

and LDO to be supplied, thus enabling proper system operations.

The CEN pin must be left floating or tied high (LDO level) during the power-on for proper

operations. The STBC03 can be also turned on when VIN is outside the valid range, below

the conditions that the battery has at least a remaining charge of 3 V and the wake-up input

is properly triggered. The STBC03 features an UVLO circuit that prevents oscillations if the

input voltage source is unstable. The CEN pin must be left floating or tied to a high level

(LDO) when the STBC03 is powered.

8.2

Battery charger

The STBC03 allows single-cell Li-Ion and Li-Poly battery chemistry to be charged up to a

4.45 V using a CC/CV charging algorithm. The charging cycle starts when a valid input

a high impedance state to a low logic level.

charger enters the pre-charge phase and starts charging in constant-current mode with the