BQ2057CSN BENCHMARQ, BQ2057CSN Datasheet - Page 12

• Manufacturer Part Number: BQ2057CSN
• Description: PROG BATTERY CHARGER, 2057, SOIC8
• Manufacturer: BENCHMARQ

Specifications of BQ2057CSN

• Battery Type: Li-Ion / Li-Polymer
• Input Voltage: 15V
• Battery Charge Voltage: 4.2V
• Charge Current Max: 2A
• Battery Ic Case Style: SOIC
• No. Of Pins: 8
• No. Of Series Cells: 1
• Operating Temperature: RoHS Compliant

12
SLUS025F − MAY 2001 − REVISED JULY 2002
charge termination and recharge
battery temperature monitoring
DC+
DC−
R SNS
The bq2057 monitors the charging current during the voltage-regulation phase. The bq2057 declares a done
condition and terminates charge when the current tapers off to the charge termination threshold, I
charge cycle begins when the battery voltage falls below the V
The bq2057 continuously monitors 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 9.) The bq2057 compares this voltage against its internal V
thresholds to determine if charging is allowed. (See Figure 10.) The temperature sensing circuit is immune to
any fluctuation in V
are referenced to VCC.
The resistor values of R
Figure 7. Optional Voltage Divider for
For NTC Thermistors
Nonstandard Regulation Voltage,
(High-Side Current Sensing)
R
R
T1
T2
SNS
BAT
VCC
TS
+
+
bq2057
3
5
2
CC
COMP
5
STAT
R
R
VSS
, since both the external voltage divider and the internal thresholds (V
R
CC
TH
TC
(T1)
TC
R
TH
* R
and R
– 7
R
TC
TH
R B1
R B2
R
APPLICATION INFORMATION
(T2)
TC
R
TH
are calculated by the following equations:
BAT+
BAT−
www.ti.com
DC−
DC+
Figure 8. Optional Voltage Divider for
Nonstandard Regulation Voltage,
(RCH)
(Low-Side Current Sensing)
threshold.
SNS
BAT
VCC
TS
bq2057
COMP
STAT
VSS
CC
R SNS
R B1
R B2
(TS1)
(TS1)
(TERM)
and V
and V
. A new
BAT+
BAT−
(TS2)
(TS2)
(3)
(4)
)