BQ2057CSN BENCHMARQ, BQ2057CSN Datasheet - Page 11

• 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

voltage regulation phase
DC+
DC−
The voltage regulation feedback is through the BAT pin. This input is tied directly to the positive side of the
battery pack. The bq2057 monitors the battery-pack voltage between the BAT and VSS pins. The bq2057 is
offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V and 8.4 V.
Other regulation voltages can be achieved by adding a voltage divider between the positive and negative
terminals of the battery pack and using bq2057T or bq2057W. The voltage divider presents scaled battery-pack
voltage to BAT input. (See Figure 7 and Figure 8.) The resistor values RB1 and RB2 for the voltage divider are
calculated by the following equation:
Where:
Figure 5. High-Side Current Sensing
N = Number of cells in series
V
R SNS
(CELL)
R
R
B1
B2
= Desired regulation voltage per cell
+
SNS
BAT
VCC
TS
N
bq2057
V
COMP
V
STAT
O(REG)
VSS
(CELL)
CC
APPLICATION INFORMATION
–1
BAT+
BAT−
www.ti.com
DC+
DC−
Figure 6. Low-Side Current Sensing
SNS
BAT
VCC
TS
SLUS025F − MAY 2001 − REVISED JULY 2002
bq2057
R SNS
COMP
STAT
VSS
CC
BAT+
BAT−
(2)
11