BQ2057DGKR Datasheet, PDF (14/24 Pages) Texas Instruments – ADVANCED LINEAR CHARGE MANAGEMENT IC FOR SINGLE AND TWO CELL LITHIUM-POLYMER

bq2057, bq2057C
bq2057T, bq2057W
SLUS025F − MAY 2001 − REVISED JULY 2002
APPLICATION INFORMATION
charge inhibit function
The TS pin can be used as charge-inhibit input. The user can inhibit charge by connecting the TS pin to VCC
or VSS (or any level outside the V_(TS1) to V_(TS2) thresholds). Applying a voltage between the V_(TS1) and V_(TS2)
thresholds to pin TS returns the charger to normal operation.
charge status indication
The bq2057 reports the status of the charger on the 3-state STAT pin. The following table summarized the
operation of the STAT pin.
CONDITION
Battery conditioning and charging
Charge complete (Done)
Temperature fault or sleep mode
STAT PIN
High
Low
Hi-Z
The STAT pin can be used to drive a single LED (Figure 1), dual-chip LEDs (Figure 4) or for interface to a host
or system processor (Figure 11). When interfacing the bq2057 to a processor, the user can use an output port,
as shown in Figure 11, to recognize the high-Z state of the STAT pin. In this configuration, the user needs to
read the input pin, toggle the output port and read the STAT pin again. In a high-Z condition, the input port always
matches the signal level on the output port.
bq2057CTS
SNS
BAT
VCC
TS
COMP
CC
VSS
STAT
Host
Processor
OUT
IN
Figure 11. Interfacing the bq2057 to a Host Processor
low-power sleep mode
The bq2057 enters the sleep mode if the VCC falls below the voltage at the BAT input. This feature prevents
draining the battery pack during the absence of VCC.
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