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TYPICAL APPLICATION CIRCUIT

AC Adapter

VDC

GND

C

IN

1

7

2

5

4

6

8

bq24316DSG

bq24080

ChargerIC

SYSTEM

IN

OUT

VBAT

FAULT

CE

C

OUT

C

OUT

R

BAT

R

CE

Host

Controller

R

FAULT

V

PU

R

PU

1

F

m

1

F

m

100kW

47kW

47kW

47kW

R

ILM

25kW

DETAILED FUNCTIONAL DESCRIPTION

POWER DOWN

POWER-ON RESET

bq24314

bq24316

SLUS763C – JULY 2007 – REVISED OCTOBER 2007

Figure 23.

The bq24314 and bq24316 are highly integrated circuits designed to provide protection to Li-ion batteries from

failures of the charging circuit. The IC continuously monitors the input voltage, the input current and the battery

voltage. In case of an input overvoltage condition, the IC immediately removes power from the charging circuit by

turning off an internal switch. In the case of an overcurrent condition, it limits the system current at the threshold

value, and if the overcurrent persists, switches the pass element OFF after a blanking period. If the battery

voltage rises to an unsafe level, the IC disconnects power from the charging circuit until the battery voltage

returns to an acceptable value. Additionally, the IC also monitors its own die temperature and switches off if it

becomes too hot. The input overcurrent threshold is user-programmable. The IC can be controlled by a

processor, and also provides status information about fault conditions to the host.

The device remains in power down mode when the input voltage at the IN pin is below the undervoltage

Hi-Z.

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

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 2 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 3.

10

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Product Folder Link(s): bq24314 bq24316