BQ24195 Datasheet, PDF (25/41 Pages) Texas Instruments – I2C Controlled 2.5A / 4.5A Single Cell USB/Adapter Charger With 5.1V at 1A / 5.1V at 2.1A Synchronous Boost Operation

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VREF
V_LTF
V_LTFH
TEMPERATURE RANGE TO
INITIATE CHARGE
CHARGE SUSPENDED
CHARGE at full C
bq24195
bq24195L
SLUSB97 – OCTOBER 2012
TEMPERATURE RANGE
DURING A CHARGE CYCLE
CHARGE SUSPENDED
VREF
V_LTF
V_LTFH
CHARGE at full C
V_HTF
AGND
CHARGE SUSPENDED
CHARGE SUSPENDED
Figure 21. TS Pin Thermistor Sense Thresholds
V_TCO
AGND
Assuming a 103AT NTC thermistor is used on the battery pack , the value RT1 and RT2 can be determined by
using the following equation:
RT2 =
V_VREF
´ RTH_COLD
´ RTH_HOT
æ
´ç
è
1
V_LTF
-
1
V_TCO
ö
÷
ø
RTH_HOT
´
æ
ç
V_VREF
è ^VTCO
-
ö
1_÷
ø
-
RTH_COLD
´
æ
ç
è
V_VREF
V_LTF
ö
- 1_÷
ø
V_{VREF - 1}
RT1 =
V_LTF
1₊ 1
RT2 RTH_COLD
(1)
Select 0°C to 45°C range for Li-ion or Li-polymer battery,
RTH_COLD = 27.28 kΩ
RTH_HOT = 4.911 kΩ
RT1 = 5.52 kΩ
RT2 = 31.23 kΩ
Charging Termination
The bq24195L, bq24195 terminates a charge cycle when the battery voltage is above recharge threshold, and
the current is below termination current. After the charging cycle is complete, the BATFET turns off. The
converter keeps running to power the system, and BATFET can turn back on to engage supplement mode.
When termination occurs, the status register REG09[5:4] is 11, and an INT is asserted to the host. Termination is
temporarily disabled if the charger device is in input current/voltage regulation or thermal regulation. Termination
can be disabled by writing 0 to REG05[7].
Termination when REG02[0] = 1
When REG02[0] is HIGH to reduce the charging current by 80%, the charging current could be less than the
termination current. The charger device termination function should be disabled. When the battery is charged to
fully capacity, the host disables charging through CE pin or REG01[5:4].
Copyright © 2012, Texas Instruments Incorporated
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