BQ24083_16 Datasheet, PDF (13/24 Pages) Texas Instruments – ADJUSTABLE BATTERY VOLTAGE

bq24083
www.ti.com .............................................................................................................................................................. SLUS848A – MAY 2008 – REVISED APRIL 2009
Charge Status Outputs
The open-drain STAT1 and STAT2 outputs indicate various charger operations as shown in the following table.
These status pins can be used to drive LEDs or communicate to the host processor. Note that OFF indicates the
open-drain transistor is turned off.
Table 1. Status Pin Summary
CHANGE STATE
Precharge in progress
Fast charge in progress
Charge done
Charge suspend (temperature)
Timer fault
Sleep mode
STAT1
ON
ON
OFF
OFF
STAT2
ON
OFF
ON
OFF
PG Output
The open-drain power-good (PG) output pulls low when a valid input voltage is present. This output is turned off
(high-impedance) in sleep mode. The PG pin can be used to drive an LED or communicate to the host
processor.
Charge-Enabled (CE) Input
The CE digital input is used to disable or enable the charge process. A low-level signal on this pin enables the
charge and a high-level signal disables the charge and places the device in a low-power mode. A high-to-low
transition on this pin also resets all timers and timer fault conditions.
Battery Voltage Selection, (VBSEL) Input
The VBSEL input is used to select the output voltage of bq24083. A low level signal on this pin selects the
charge voltage of 4.2 V. A high level voltage selects the charge voltage of 4.06 V. If VBSEL is left open, an
internal current source flowdown ensures the charge voltage is set to 4.2 V (typical).
Timer Fault and Recovery
As shown in Figure 7, the device provides a recovery method to deal with timer fault conditions. The following
summarizes this method:
Condition Number 1
OUT pin voltage is above the recharge threshold (V_(RCH)), and a timeout fault occurs.
Recovery method: the device waits for the OUT pin voltage to fall below the recharge threshold. This could
happen as a result of a load on the battery, self-discharge, or battery removal. Once the OUT pin voltage falls
below the recharge threshold, the device clears the fault and starts a new charge cycle. A POR or CE toggle also
clears the fault.
Condition Number 2
OUT pin voltage is below the recharge threshold (V_(RCH)), and a timeout fault occurs
Recovery method: Under this scenario, the device applies the I_(FAULT) current. This small current is used to detect
a battery removal condition and remains on as long as the battery voltage stays below the recharge threshold. If
the OUT pin voltage goes above the recharge threshold, then the device disables the I_(FAULT) current and
executes the recovery method described for condition number 1. Once the OUT pin voltage falls below the
recharge threshold, the bq24083 clears the fault and starts a new charge cycle. A POR or CE toggle also clears
the fault.
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