Datasheet

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CoreOscillatorFrequency-kHz
I Current- A
TMR
m
CHARGE TERMINATION DETECTION AND RECHARGE
BATTERY ABSENT DETECTION – VOLTAGE MODE ALGORITHM
bq2406x
SLUS689A – JUNE 2006 – REVISED OCTOBER 2006
Figure 22. bq2406x Oscillator Linearity vs I
TMR
R
TMR
30 K Ω – 100 K Ω
The charging current is monitored the during the voltage regulation phase. Charge termination is indicated at the
STATx pins (STAT1 = Hi-Z; STAT2 = Low ) 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.
Table 6 describes the termination latch functionality.
Table 6. Termination Latch Functionality
TERMINATION DETECTED LATCHED WHEN TERMINATION LATCH RESET AT
CE rising edge or OVP detected
I(OUT) < I
(TERM)
AND t > T
DGL(TERM)
AND V(OUT) > V
(RCH)
New charging cycle started; see state diagram
Termination disabled
The termination function is DISABLED:
1. In bq24060/61/64 the termination is disabled when the TMR pin is left open (floating).
2. In bq24063 leaving TMR pin open (floating) does NOT disable the termination. The only way to disable
termination in the bq24063 is to set TE = HIGH.
The bq2406x provides a battery absent detection scheme to reliably detect insertion and/or removal of battery
packs. The detection circuit applies an internal current to the battery terminal, and detects battery presence
based on the terminal voltage behavior. Figure 23 has a typical waveform of the output voltage when the battery
absent detection is enabled and no battery is connected:
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