Datasheet

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2.75 A
500 mA
200 mA
750 mA
800 mA
300 mA
-250 mA
SYSTEMLOAD
INPUT
CURRENT
BATTERY
CHARGE
CURRENT
BATTERY
CHARGING,
USBINPUT LIMIT
SET TO 2.75 A
BATTERY
CHARGING,
INPUT LIMIT SET
TO 500 mA
BATTERY
DISCHARGING,
SUPPLEMENT
MODESET
(800mA DEFINED
BY RSET VALUE)
I(USB)
I(OUT )
CHARGE TERMINATION AND RECHARGE
I
TERM
+
V
TERM
K
SET
R
SET
(4)
TPS65810
TPS65811
SLVS658B – MARCH 2006 – REVISED FEBRUARY 2007
The ISET1 resistor always sets the maximum charge current if the AC input is selected. When the USB input is
selected, the maximum charge current is defined by the USB input current limit and the programmed charge
current. If the USB input current limit is lower than the I
O(OUT)
value, the battery switch is set in the dropout region
and the charge current is defined by the input current limit value and system load, as shown in the following
curves:
Figure 36. Input Current Limit Impact on Effective Charge Current
The TPS65810 monitors the charging current during the voltage regulation phase. Charge is terminated when
the charge current is lower than an internal threshold, set to 10% (typ) of the fast charge current rate. The
termination point applies to both AC and USB charging, and it can be calculated as follows:
where
V
TERM
is the termination detection voltage reference.
The voltage at ISET1 pin is monitored to detect termination, and termination is detected when V(SET1) < V
TERM
(0.25 V typ). The voltage reference V
TERM
is internally set to 10% of the V
SET
reference voltage, and it is modified
if the reference voltage V
SET
is scaled via I
2
C register CHG_CONFIG bits ISET1_1 and ISET1_0. V
TERM
is
reduced by the same percentage used to scale down V
SET
.
The table below shows charge current and termination thresholds for a 1-A charge current set (1-k Ω resistor
connected to ISET1 pin), with the selected input current limit set to a value higher than the programmed charge
current. The termination current is scaled for all charge current modes (AC or USB), as it is always set by the
ISET1 pin external resistor value.
Table 7. Charge Current and Termination Threshold Selection Example
Charge Control Register Bits Charge Current, (% of typical value Vset Vterm Charge Termination
programmed by ISET1 resistor) (V) (mV) Current (A) Current (mA)
ISET1_1 ISET1_0
0 0 25% 0.6 60 0.24 20
0 1 50% 1.25 115 0.5 40
1 0 75% 1.9 160 0.78 60
1 1 100% 2.5 250 1 100
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