BQ24620 Datasheet, PDF (18/30 Pages) Texas Instruments – Stand-Alone Synchronous Switch-Mode Lithium Phosphate Battery Charger with Low Iq

bq24620
SLUS893 – MARCH 2010
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be within the V(LTF) to V(TCO) thresholds. If battery temperature is outside of this range, the controller suspends
charge and safety timer and waits until the battery temperature is within the V(LTF) to V(HTF) range. If the
battery temperature is between the V(LTF) and the V(COOL) thresholds or between the V(HTF) and V(WARM)
thresholds, charge is automatically reduced to I_CHARGE/8. To avoid early termination during COOL/WARM
condition, set I_TERM ≤ I_CHARGE/10. The controller suspends charge by turning off the PWM charge FETs. Figure 12
and Figure 13 summarizes the operation.
VREF
TEMPERATURE RANGE TO
INITIATE CHARGE
TEMPERATURE RANGE
DURING A CHARGE CYCLE
VREF
CHARGE SUSPENDED
CHARGE SUSPENDED
V_{LTF_}^V_HLYTFS
V_COOL
V_{COOL_HYS}
CHARGE at I_CHARGE/8
CHARGE at I_CHARGE/8
V_LTF
V_COOL
V_WARM
V_{WARM_HYS}
CHARGE at I_CHARGE
CHARGE at I_CHARGE
V_HTF
CHARGE at I_CHARGE/8
CHARGE at I_CHARGE/8
CHARGE SUSPENDED
CHARGE SUSPENDED
GND
Figure 12. TS, Thermistor Sense Thresholds
V_WARM
V_TCO
GND
Charge
Current
Charge
Suspended
Programmed
Charge Current
(I_CHARGE)
Charge at I_CHG
Charge
Suspended
1/8 x Programmed
Charge Current
(I_CHARGE/8)
V_LTF V_COOL
V_WARM V_HTF/V_TCO ^Temperature
Figure 13. Typical Charge Current vs Temperature Profile
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