bq24314C

SLUSAV3A – AUGUST 2012 – REVISED JULY 2015

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7.4 Device Functional Modes

7.4.1 OPERATION Mode

The device continuously monitors the input voltage, the input current, and the battery voltage. As long as the

input voltage is less than VOVP, the output voltage tracks the input voltage (less the drop caused by RDSON of

Q1). During fault conditions, the internal FET is turned off and the output is isolated from the input source.

7.4.2 POWER-DOWN Mode

The device remains in POWER-DOWN mode when the input voltage at the IN pin is below the undervoltage

threshold UVLO. The FET Q1 connected between IN and OUT pins is off, and the status output, FAULT, is set to

Hi-Z. See Figure 9.

7.4.3 POWER-ON RESET Mode

The device resets when the input voltage at the IN pin exceeds the UVLO threshold. All internal counters and

feature to control the inrush current. The soft-start minimizes the ringing at the input (the ringing occurs because

the parasitic inductance of the adapter cable and the input bypass capacitor form a resonant circuit). Figure 13

shows the power-up behavior of the device. Because of the deglitch time at power-on, if the input voltage rises

rapidly to beyond the OVP threshold, the device will not switch on at all, instead it will go into protection mode

and indicate a fault on the FAULT pin, as shown in Figure 14.

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