BQ25015 Datasheet, PDF (13/28 Pages) Texas Instruments – SINGLE-CHIP CHARGER AND DC/DC CONVERTER IC FOR PORTABLE APPLICATIONS

bq25015
bq25017
www.ti.com
SLUS721A – DECEMBER 2006 – REVISED MARCH 2007
FUNCTIONAL DESCRIPTIONS (continued)
The bq25015/7 resets the taper timer in the event that the charge current returns above the taper threshold,
I_(TAPER).
In addition to the taper current detection, the bq25015/7 terminates charge in the event that the charge current
falls below the I_(TERM) threshold. This feature allows for quick recognition of a battery removal condition or
insertion of a fully charged battery. Note that taper timer is not activated. The resistor connected between the
ISET1 and VSS pins, R_SET, determines the taper detection level. The V_(TERM) and K_(SET) parameters are
specified in the specifications table. Note that this applies to both AC and USB charging.
I _(TERM)
+
V_(TERM) K_(SET)
R_SET
(4)
After charge termination, the bq25015/7 restarts the charge once the voltage on the BAT/OUT pin falls below the
V_(RCH) threshold. This feature keeps the battery at full capacity at all times.
Sleep Mode for Charger
The bq25015/7 enters the low-power sleep mode if both AC and USB are removed from the circuit. This feature
prevents draining the battery during the absence of V_CC.
Operation Modes
Operational modes of the bq25015/7 are summarized in Table 1. Operation of DC-DC is not recommended
while charger is in precharge mode.
BATTERY VOLTAGE
V_I(BAT) > V_(LOWV)
0 V < V_I(BAT) < V_(LOWV)
V_I(BAT) < V_(UVLO)
Table 1. Operation Modes
AC or USB ADAPTER STATUS
Present
Present
Both absent
CHARGER STATUS
Fast
Precharge
Off
DC-DC STATUS
EN
EN
Off
Status Outputs
The STAT1 and STAT2 open-drain outputs indicate various charger and battery conditions as shown in Table 2.
These status pins can be used to communicate to the host processor. Note that OFF indicates the open-drain
transistor is turned off.
CHARGE STATE
Precharge in progress
Fast charge in progress
Charge done
Timer fault
Speel mode
Table 2. Status Pins Summary
INPUT POWER STATE
Present
Present
Not reported
Not reported
Absent
STAT1
ON
ON
OFF
OFF
OFF
STAT2
ON
OFF
ON
OFF
OFF
PG Output (Power Good)
The open-drain PG output indicates when the AC adapter is present. The output turns ON when a valid voltage
is detected. This output is turned off in the sleep mode. The PG pin can be used to drive an LED or
communicate to the host processor.
CE Input (Charge Enable)
The CE digital input is used to enable or disable 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 into a low-power mode. A high-to-low
transition on this pin also resets all timers and timer fault conditions. Note that this applies to both AC and USB
charging.
Submit Documentation Feedback
13