SLUU110A Datasheet, PDF (11/21 Pages) Texas Instruments – BQ2004/5/6 DUAL-CELL LI-LON CHARGER

Test Procedures
Note:
For the two-cell case, at 1-A charge rate, where the battery pack is at 6 V,
the power dissipation is temporarily as high as 3.1 W until the pack charges
to 6.8 V. This condition is fine for the short time (~1 min.) before the pack
reaches 6.8 V.
Adjust the input power supply for 9.1 V. The red LED illuminates to indicate
charging, unless there is a fault or the battery is fully charged.
The bq24004/5/6 enters preconditioning mode if the battery is below the LowV
threshold. In this mode, the bq24004/5/6 trickle-charges with approximately
65 mA for approximately 23 minutes. If the battery does not reach the LowV
threshold during this period, then the charge current is terminated and the
bq24004/5/6 enters fault mode. The red LED flashes in fault mode. This
feature may be tested by removing input power, replacing the battery with a
30–40-Ω resistor from BAT+ to DC–, and applying power (Vin) for more than
23 minutes. Fault mode is reset by toggling input power or enable pin.
Once the battery charges to the LowV-stop threshold, the battery enters fast-
charge mode and charges at the programmed 1-A level. Program charge level
ǒ Ǔ may be changed by adjusting R3
R3
+
0.10 V
Ichg
.
The battery remains at the fast-charge mode until either the selected time
expires or the battery charges to the selected regulation voltage.
The time-out feature is tested by using a 25–28-Ω, 5-W resistor in place of the
battery. Apply the resistor after the unit is powered.
If the battery discharges down to the HighV threshold, the charger starts fast
charging. The refresh feature may be tested by charging a battery to
completion (I_term + 23 minutes) and, without disconnecting the battery,
installing a 8–10-Ω, 10-W resistor in parallel with the battery. The regulator
should start charging once the HIGHV threshold is reached. Note: The battery
is still charging for another 23 minutes after the LED turns off. If a load (>Iterm)
is applied before the 23 minutes has timed out then the load resets the 23
minute timer.
The circuit has an overvoltage comparator for added protection. If the battery
voltage exceeds this threshold for 330 ms, then the charger goes into fault
mode. This may be tested by connecting an external power supply in place of
the battery and adjusting the voltage above the threshold.
Test Summary
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