Datasheet

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I
(TAPER)
+
V
(TAPER)
K
(SET)
R
SET
(3)
I
(TERM)
+
V
(TERM)
K
(SET)
R
SET
(4)
Sleep Mode for Charger
Operation Modes
Status Outputs
PG Output (Power Good)
bq25010
bq25011
bq25012
SLUS615B – DECEMBER 2004 – REVISED JULY 2007
The bq2501x 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 bq2501x 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.
After charge termination, the bq2501x 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.
The bq2501x 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
.
Operational modes of the bq2501x are summarized in Table 1 . Operation of DC-DC is not recommended while
charger is in precharge mode.
Table 1. Operation Modes
BATTERY VOLTAGE AC or USB ADAPTER STATUS CHARGER STATUS DC-DC STATUS
V
I(BAT)
> V
(LOWV)
Present Fast EN
0 V < V
I(BAT)
< V
(LOWV)
Present Precharge EN
V
I(BAT)
< V
(UVLO)
Both absent Off Off
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.
Table 2. Status Pins Summary
CHARGE STATE INPUT POWER STATE STAT1 STAT2
Precharge in progress Present ON ON
Fast charge in progress Present ON OFF
Charge done Not reported OFF ON
Timer fault Not reported OFF OFF
Speel mode Absent OFF OFF
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.
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Product Folder Link(s): bq25010 bq25011 bq25012