BQ2406X Datasheet, PDF (13/31 Pages) Texas Instruments – 1A SINGLE-CHIP Li-Ion/Li-Pol CHARGE MANAGEMENT IC WITH THERMAL REGULATION

bq2406x
www.ti.com
SLUS689 – JUNE 2006
CONTROL LOGIC OVERVIEW
An external host can enable or disable the charging process using a dedicated control pin, CE. A low-level
signal on this pin enables the charge, and a high-level signal disables the charge. The bq2460x is in stand-by
mode with CE = HI. When the charger function is enabled (CE = LO) a high accuracy reference is activated, to
provide the charge voltage and charge current internal references.
The charger power stage is turned on if CE = LO and if the bq2406X detects that all conditions for safely
charging a battery exist. Table 1 describes the charger control logic operation, in bq2460x versions without the
TS pin the pack temp status is internally set to OK.
Table 1. Control Logic Functionality
CE INPUT
TIMER
OUTPUT TERMINATION
POWER FAULT
SHORT
(latched)
(latched) CIRCUIT
PACK
TEMP
THERMAL POWER
SHUTDOWN DOWN
CHARGER bq2460X
POWER OPERATION
STAGE
MODE
LO
X
X
X
X
X
X
Yes
OFF
POWER
DOWN
X
Not
X
X
X
X
X
No
OFF
SLEEP
Detected
HI Detected
X
X
X
X
X
No
OFF
STANDBY
LO Detected
X
Yes
X
X
X
No
SEE STATE
LO Detected
No
No
Yes
X
X
No
OFF
DIAGRAM
LO Detected
Yes
No
No
X
X
No
IFAULT
LO Detected
No
No
LO Detected
No
No
LO Detected
No
No
LO
Over
No
No
Voltage
Yes
Absent
T_J < T_SHUT
No
IDETECT
No
Hot or Cold T_J < T_SHUT
No
OFF
No
Ok
T_J < T_SHUT
No
OFF
No
Ok
T_J < T_SHUT
No
OFF
LO Detected
No
No
No
Ok
T_J < T_SHUT
No
ON
CHARGING
In both STANDBY and SUSPEND modes the charge process is disabled. In the STANDBY mode all timers are
reset; in SUSPEND mode the timers are held at the count stored when the suspend mode was set.
The timer fault, termination and output short circuit variables shown in the control logic table are latched in the
detection circuits, outside the control logic. Refer to the timers, termination and short circuit protection sections
for additional details on how those latched variables are reset.
The following states do not happen simultaneously due to the implementation of state machine flow:
• Termination detected and timer fault detected
• Battery absent function enabled when termination is not detected
TEMPERATURE QUALIFICATION (Applies only to versions with TS pin option)
The bq24060/62/64/65 devices continuously monitor the battery temperature by measuring the voltage between
the TS and VSS pins. The IC compares the voltage on the TS pin against the internal V_(TS1) and V_(TS2)
thresholds to determine if charging is allowed. Once a temperature outside the V_(TS1) and V_(TS2) thresholds is
detected the IC immediately suspends the charge. The IC suspends charge by turning off the power FET and
holding the timer value (i.e., timers are NOT reset). Charge is resumed when the temperature returns to the
normal range.
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