Temperature Monitoring

The bq24401 measures the temperature by the voltage at

the TS pin. This voltage is typically generated by a nega-

tive-temperature-coefficient thermistor. The bq24401

compares this voltage against its internal threshold

voltages to determine if charging is safe.

These thresholds are the following:

l

This voltage corresponds to the maximum temperature

(TCO) at which fast charging is allowed. The bq24401

terminates fast charge if the voltage on pin TS falls

l

voltage corresponds to the temperature (HTF) at which

fast charging is allowed to begin.

l

This voltage corresponds to the minimum temperature

(LTF) at which fast charging or top-off is allowed. If the

suspends fast charge or top-off but does not terminate

charge or top-off resumes from the point where

suspended. Trickle-charge is allowed during this

condition.

Table 3 summarizes these various conditions.

Charge Status Display

The charge status is indicated by open-drain output LED.

Table 4 summarizes the display output of the bq24401.

Sleep Mode

The bq24401 features a sleep mode for low power con-

sumption. This mode is enabled when the voltage at pin

ing sleep mode, the bq24401 shuts down all internal cir-

cuits, drives the LED output to high-impedance state,

and drives pin MOD to low. Restoring BAT below the

cycle.

9

bq24401

2000TCS.eps

BAT-

Power Supply ground

bq2000 ground

SNS

1

2

bq2000T

Figure 8. Current-Sensing Circuit

Absolute Maximum Ratings

Symbol

Parameter

Minimum

Maximum

Unit

Notes

-0.3

+7.0

V

DC voltage applied on any pin, ex-

-0.3

+7.0

V

Operating ambient temperature

-20

+70

°C

Storage temperature

-40

+125

°C

Soldering temperature

-

+260

°C

10s max.

Note:

Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation

should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to

conditions beyond the operational limits for extended periods of time may affect device reliability.

bq24401

bq24401