8.3 Feature Description

8.3.1 Device Power Up

The EN pin enable or disable the device. When the device is disabled, the device draws minimum current from

VBUS pin. POL grouding or floating determines the polority of the EN pin. The device can be powered up from

either VBUS or by enabling the device from EN pin.

8.3.1.1 Power-On-Reset (POR)

The EN pin can enable or disable the device. When the device is disabled, the device is in disable mode and it

powers part of internal bias and comparators and starts Power on Reset (POR).

8.3.1.2 REGN Regulator Power Up

The internal bias circuits are powered from the input source. The REGN supplies internal bias circuits as well as

the HSFET and LSFET gate drive. The REGN also provides voltage rail to STAT LED indication. The REGN is

enabled when all the below conditions are valid:

• Chip is enabled by EN pin

• After sleep comparator deglitch time, VSET detection time, and REGN delay time

REGN remains on at fault conditions. REGN is powered by VBUS only and REGN is off when VBUS power is

removed.

8.3.1.3 Charger Power Up

Following REGN power-up, if there is no fault conditions, the charger powers up with soft start. If there is any

fault, the charger will remain off until fault is clear. Any of the fault conditions below gates charger power-up:

• Thermistor cold/hot fault on TS pin

• Safety timer fault

• ICHG pin is open or short to GND

• Die temperature is above TSHUT

8.3.1.4 Charger Enable and Disable by EN Pin

The charger can be enabled or disabled by EN pin pulled high or low. The charger is in disable mode when

disabled.

8.3.1.5 Device Unplugged from Input Source

8.3.2 Battery Charging Management

The BQ25302 charges 1-cell Li-Ion battery with up to 2.0-A charge current from 4.1-V to 6.2-V input voltage. A

new charge cycle starts when the charger power-up conditions are met. The charge voltage is set by external

resistor connected at VSET pin and charge current are set by external resistors at ICHG pin. The charger

fully charged battery's voltage is discharged below recharge threshold, the device automatically starts a new

charging cycle with safety timer reset. To initiate a recharge cycle, the conditions of charger power-up must be

met. The STAT pin output indicates the charging status of charging (LOW), charging complete or charge

disabled (HIGH) or charging faults (BLINKING).

BQ25302

SLUSCZ3 – OCTOBER 2020

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