BQ24081_12 Datasheet, PDF (13/25 Pages) Texas Instruments – 1-A, SINGLE-CHIP, LI-ION AND LI-POL CHARGER IC

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bq24080
bq24081
SLUS698E – MARCH 2006 – REVISED AUGUST 2011
Sleep Mode
The device enters the low-power sleep mode if the input power (IN) is removed from the circuit. This feature
prevents draining the battery during the absence of input supply.
Charge Status Outputs
The open-drain STAT1 and STAT2 outputs indicate various charger operations as shown in the following table.
These status pins can be used to drive LEDs or communicate to the host processor. Note that OFF indicates the
open-drain transistor is turned off.
Table 1. Status Pin Summary
CHANGE STATE
Precharge in progress
Fast charge in progress
Charge done
Charge suspend (temperature)
Timer fault
Sleep mode
STAT1
ON
ON
OFF
OFF
STAT2
ON
OFF
ON
OFF
PG Output (bq24080)
The open-drain power-good (PG) output pulls low when a valid input voltage is present. This output is turned off
(high-impedance) in sleep mode. The PG pin can be used to drive an LED or communicate to the host
processor.
Charge-Enabled (CE) Input (bq24080)
The CE digital input is used to disable or enable the charge process. A low-level signal on this pin enables the
charge and a high-level signal disables the charge and places the device in a low-power mode. A high-to-low
transition on this pin also resets all timers and timer fault conditions.
Timer Enabled (TE) Input (bq24081)
The TE digital input is used to disable or enable the fast-charge timer. A low-level signal on this pin enables the
fast-charge timer, and a high-level signal disables this feature.
TEMPERATURE QUALIFICATION (bq24081)
The bq24081 continuously monitors battery temperature by measuring the voltage between the TS and V_SS pins.
An internal current source provides the bias for common 10-kΩ negative-temperature-coefficient thermistors
(NTC) (see the functional block diagram). The device compares the voltage on the TS pin with the internal V_(TS1)
and V_(TS2) thresholds to determine if charging is allowed. If a temperature outside the V_(TS1) and V_(TS2) thresholds
is detected, the device immediately suspends the 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 within the normal range.
The allowed temperature range with a 103AT-type thermistor is 0°C to 45°C. However, the user may modify
these thresholds by adding external resistors (see Figure 8 and Figure 9
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