Datasheet

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NormalTemperature
ChargeRange
V
0.3*V
C(TS1)
IN
ChargeSuspend
ChargeSuspend
V
IN
V
0.6*V
C(TS2)
IN
R
T2
+
2.5 R
TC
R
TH
R
TC
* 3.5 R
TH
(1)
R
T1
+
7 R
TH
R
T2
3
ƪ
R
TH
) R
T2
ƫ
(2)
INPUT OVERVOLTAGE DETECTION, POWER GOOD STATUS OUTPUT
CHARGE STATUS OUTPUTS
bq2406x
SLUS689A – JUNE 2006 – REVISED OCTOBER 2006
Figure 18. Battery Temperature Qualification With NTC Thermistor
The external resistors R
T1
and R
T2
(see application diagram) enable selecting a temperature window. If R
TC
and
R
TH
are the thermistor impedances for the Cold and Hot thresholds the values for R
T1
and R
T2
can be calculated
as follows, for a NTC (negative temperature coefficient) thermistor. Solve for R
T2
first and substitute into R
T1
equation.
Applying a fixed voltage, 1/2 Vin (50% resistor divider from Vin to ground), to the TS pin to disable the
temperature sensing feature.
The input power detection status for pin IN is shown at the open collector output pin PG.
Table 2. Input Power Detection Status
INPUT POWER DETECTION (IN) PG STATE
NOT DETECTED High impedance
DETECTED, NO OVERVOLTAGE LO
DETECTED, OVERVOLTAGE High impedance
The bq2406x detects an input overvoltage when V(IN) > V
(OVP)
. When an overvoltage protection is detected the
charger function is turned off and the bq2460x is set to standby mode of operation. The OVP detection is not
latched, and the IC returns to normal operation when the fault condition is removed.
The open-collector STAT1 and STAT2 outputs indicate various charger operations as shown in Table 3 . These
status pins can be used to drive LEDs or communicate to the host processor. Note that OFF indicates the
open-collector transistor is turned off. When termination is disabled (TMR pin floating or TE = Hi, bq24063) the
Done state is not available; the status LEDs indicate fast charge if V
BAT
> V
LOWV
and precharge if V
BAT
< V
LOWV
.
The available output current is a function of the OUT pin voltage, See Figure 24 .
16
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