BQ24070RHLRG4 Datasheet, PDF (16/31 Pages) Texas Instruments – SINGLE-CHIP LI-ION CHARGE AND SYSTEM POWER-PATH MANAGEMENT IC

bq24070
bq24071
SLUS694F – MARCH 2006 – REVISED DECEMBER 2009
www.ti.com
input current (0.2 A/div); Mode = Low; CE = High; ISET2 = High; V_BAT = 3.85 V; V_(DPPM) = 3.0 V (V_(DPPM) × 1.15 <
V_BAT, otherwise DPPM mode increases time duration). When a USB source is applied (if AC is not present), the
CE pin and ISET2 pin are ignored during the boot-up time and a maximum input current of 100 mA is made
available to the OUT or BAT pins. After the boot-up time, the IC implements the CE and ISET2 pins as
programmed.
V_AC
I_USB
Figure 9. USB Boot-Up Power-Up
Battery Temperature Monitoring
The bq24070/1 continuously monitors battery temperature by measuring the voltage between the TS and VSS
pins. An internal current source provides the bias for most-common 10 kΩ negative-temperature coefficient
thermistors (NTC) (see Figure 10). The device compares the voltage on the TS pin against the internal V_(LTF) and
V_(HTF) thresholds 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 11.
bq24070/1
LTF
HTF
V_LTF
V_HTF
PACK+
I_TS
PACK−
TS
12
+
NTC
BATTERY
PACK
UDG−04085
bq24070/1
LTF
HTF
V_LTF
V_HTF
I_TS
TS
12
PACK+
+
PACK−
RT1 _TEMP
NTC
BATTERY
RT2
PACK
UDG−04086
Figure 10. TS Pin Configuration
Figure 11. TS Pin Thresholds
16
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