Datasheet
V
USB
I
USB
9
TS
bqTINYIII
LTF
HTF
+
BATTERY
PACK
PACK+
PACK−
NTC
TEMP
I
TS
V
LTF
V
HTF
RT1
RT2
UDG−04086
9
TS
bqTINYIII
LTF
HTF
+
BATTERY
PACK
PACK+
PACK−
NTC
I
TS
V
LTF
V
HTF
UDG−04085
bq24030, bq24031
bq24032A, bq24035, bq24038
www.ti.com
............................................................................................................................................... SLUS618H –AUGUST 2004–REVISED OCTOBER 2009
Figure 13. USB Boot-Up Power-Up
Battery Temperature Monitoring
The bqTINY™ III-series continuously monitors battery temperature by measuring the voltage between the TS
and VSS pins. An internal current source (I
(TS)
= 100 μA, typical) provides the bias for most common 10-kΩ
negative-temperature coefficient thermistors (NTC) (see Figure 14). The device compares the voltage on the TS
pin against the internal V
(LTF)
, and V
(HTF)
thresholds (0.5 V and 2.5 V, respectively are typical) to determine if
charging is allowed. Once a temperature outside the V
(LTF)
and V
(HTF)
thresholds is detected, the device
immediately suspends the charge. The device suspends charge by turning off the power FET and holding the
timer value (i.e., timers are not reset). Charge is resumed when the temperature returns to the normal range. The
allowed temperature range for 103AT-type thermistor is 0°C to 45°C. However, the user may increase the range
by adding two external resistors. See Figure 15.
Figure 14. TS Pin Configuration Figure 15. TS Pin Thresholds
Battery Pre-Conditioning
During a charge cycle, if the battery voltage is below the V
(LOWV)
threshold (3.0 V, typical), the bqTINY III-series
applies a precharge current, I
O(PRECHG)
, to the battery. This feature revives deeply discharged cells. The resistor
connected between the ISET1 and VSS, R
SET
, determines the precharge rate. The V
(PRECHG)
and
K
(SET)
parameters are specified in the specifications table. Note that this applies to both AC and USB charging.
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Product Folder Link(s): bq24030, bq24031 bq24032A, bq24035, bq24038