SLUU110A Datasheet, PDF (8/21 Pages) Texas Instruments – BQ2004/5/6 DUAL-CELL LI-LON CHARGER

Background
1.1 Background
The bq24004/5/6 series ICs are advanced Li-Ion linear charge management
devices for highly integrated and space-limited applications. They combine
high-accuracy current and voltage regulation; FET pass-transistor and
reverse-blocking Schottky; battery conditioning, temperature, or input-power
monitoring; charge termination; charge-status indication; and charge timer in
a small, 20-lead TSSOP PowerPAD package.
The bq24004/5/6 continuously measures battery temperature using an
external thermistor. For safety reasons, the bq24004/5/6 inhibits charge until
the battery temperature is within the user-defined thresholds. Alternatively, the
user can monitor the input voltage to qualify charge. The bq24004/5/6 series
then charge the battery in three phases: preconditioning, constant current and
constant voltage. If the battery voltage is below the internal low-voltage
threshold, the bq24004/5/6 uses trickle-charge to condition the battery. A
preconditioning timer is provided for additional safety. Following
pre-conditioning, the bq24004/5/6 applies a constant-charge current to the
battery. An external sense-resistor sets the magnitude of the current. The
constant-current phase is maintained until the battery reaches the
charge-regulation voltage. The bq24004/5/6 then transitions to the constant
voltage phase. The user can configure the device for cells with either coke or
graphite anodes.
Charge is terminated by either of the following methods:
- Maximum time
- Minimum current detection plus 23-minute timeout
1.2 Performance Specification Summary
This section summarizes the performance specifications of the bq24004/5/6
EVM. Table 1–1 gives the performance specifications of the hubs.
The bq24004/5/6 automatically restarts the charge if the battery voltage falls
below an internal recharge threshold.
Table 1–1. Performance Specification Summary (Two Cell)
Specification
Test Conditions
Min Typ Max Units
Input dc voltage, V_DC
Battery charge current, I_CHG
Battery voltage regulation, V_REG
J6 set to V_CC
J6 set to GND
9.1 9.5
†V
0.9
1 1.1 A
8.35 8.40 8.45
V
8.15 8.20 8.25
Therm fault
High, T_BATMAX
Low, T_BATMIN
APG (user defined, see data sheet)
J2 set to Therm
J2 set to Therm
J2 set to APG
43 48 53
°C
0
5 10
‡
Power dissipation, P_D
(V_I-V_O) × I_load
2.3 W
† _{VI, for a 2-cell, should not exceed 9.1 VDC for the 1-A charge rate and 10.6 V for the 0.5-A charge rate. (VI is the input voltage}
to the bq2400x IC, pins 2 and 3. The power supply source voltage, at J1, is 0.1 V larger than VI because of the regulated voltage
drop across the current sense resistor, during constant current regulation.)
‡ _{If J2 is set to APG, then the chip is disabled when the input is outside of this range: 4.02 V±0.07 V and 10.76 V ±0.09 V.}
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