BQ2406X Datasheet, PDF (19/31 Pages) Texas Instruments – 1A SINGLE-CHIP Li-Ion/Li-Pol CHARGE MANAGEMENT IC WITH THERMAL REGULATION

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bq2406x
SLUS689 – JUNE 2006
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I_TMR Current - mA
Figure 9. bq2406x Oscillator Linearity vs I_TMR
R_TMR 30 KΩ – 100 KΩ
THERMAL SHUTDOWN AND PROTECTION
Internal circuits monitor the junction temperature, T_J, of the die and suspends charging if T_J exceeds an internal
threshold T_(SHUT) (155°C typ). Charging resumes when T_J falls below the internal threshold T_(SHUT) by
approximately 20°C.
CHARGE TERMINATION DETECTION AND RECHARGE
The charging current is monitored the during the voltage regulation phase. Charge termination is indicated at the
STATx pins (STAT1 = STAT2 = Hi-Z) once the charge current falls below the termination current threshold
I_(TERM). A deglitch period T_DGL(TERM) is added to avoid false termination indication during transient events.
Charge termination is not detected if the charge current falls below the termination threshold as a result of the
thermal loop activation. Termination is also not detected when charger enters the suspend mode, due to
detection of invalid pack temperature or internal thermal shutdown.
The termination detection is latched; charger is disabled if termination is detected. If the charger is disabled by
the host or a new charge cycle starts the termination latch is reset. Table 6 describes the termination latch
functionality.
Table 6. Termination Latch Functionality
TERMINATION DETECTED LATCHED WHEN
I(OUT) < I_(TERM) AND t > T_DGL(TERM) AND V(OUT) > V_(RCH)
TERMINATION LATCH RESET AT
CE rising edge of OVP detected
New charging cycle started; see state diagram
Termination disabled
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