Operation description

STBCFG01

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DocID026474 Rev 3

5.7

Shutdown mode

When SHDN pin is tied high the device enters shutdown mode. In this mode, the switching

converter turns off and it cannot be used neither in charging mode nor OTG boost mode.

LDO and fuel gauge functionality are not affected by SHDN pin.

5.8

Watchdog

A watchdog timer function can be enabled to reset the programmable register values to

power-on reset values if no I²C acknowledgments are generated for more than 45 seconds.

This function is normally disabled.

5.9

Alarms

The STBCFG01 provides an open drain active low interrupt output (IRQn) to notify the

application processor about abnormal operating conditions or generic events. The following

register types check the status of alarms and control the device:



Interrupt enable



Interrupt latch

The interrupt enable registers enable the propagation of alarms to the interrupt pin (IRQn).

The interrupt is generated (IRQn pulled low) on a rising edge of the interrupt latch bits

(assuming that the corresponding enable bit has been set).

The interrupt latch registers show the alarm conditions, which generate the interrupt.

Although the alarm condition is no longer active, once each latch register bit is set, it stays

high until the register is updated. Interrupt latch registers are updated by writing 0 to their

bits: if the alarm condition is still active the bit is kept to 1 (new interrupt is not generated); if

the alarm condition is no more active the bit is cleared. This update method assures that no

further rising edge on the latch bit is generated for alarms which have already been

signaled before the update operation. In order to release IRQn line after an interrupt

generated by the charger/OTG, the host processor has to write 0 to IRQ_CLR bit in

CHG_Cfg2 register and then back 1. The fuel gauge generated alarms share the same

enable bit (ALRM_en).

The following conditions generate an interrupt signal:



DCIN UVLO



DCIN OVP



ASD condition



Pre-charge timer expiration



Fast charge timer expiration



Watchdog timer expiration



Battery overvoltage protection (charger)



End of charge



Battery undervoltage lockout (OTG boost)







OTG output short-circuit; thermal shutdown



Low battery voltage (fuel gauge)



Low SOC (fuel gauge)