bq24200, bq24201, bq24202

bq24203, bq24204, bq24205

SLUS501A – OCTOBER 2001

7

www.ti.com

APPLICATION INFORMATION

UDG–01109

TEMP

1IN

2

VCC

3STAT

4

VSS

8

OUT

7

BAT

6

TS

5

N/C

BATTERY

PACK

C2

RT2

RT1

VCC

PACK+

PACK–

R1

C1

DC+

DC–

bq24200DGN

+

Figure 5. Low Dropout Single–Cell Li–Ion/Li–Pol Charger

functional description

The bq2420x supports a precision Li-Ion or Li-Pol charging system suitable for single-cells with either coke or

graphite anodes. Figure 5 shows an application schematic and Figure 6 shows the typical charge profile.

temperature qualification (bq24200 and bq24201 only)

The bq24200 and bq24201 continuously monitors battery temperature by measuring the voltage between the

TS and VSS pins. A negative- or a positive-temperature coefficient thermistor (NTC, PTC) and an external

voltage divider typically develop this voltage (see figure 5). The bq24200 and bq24201 compare this voltage

temperature sensing circuit is immune to any fluctuation in Vcc since both the external voltage divider and the

internal thresholds are referenced to Vcc.

suspend the charge. The bq24200 and bq24201 suspend the charge by turning off the powerFET and holding

the timer value (i.e. timers are NOT reset). Charge is resumed when the temperature returns to the normal

range.