Datasheet
Features
➤
bq2057 charge-control evaluation and development
system for single- and dual-cell Li-Ion packs with
coke or graphite anodes
➤
Optional temperature monitoring before and during
charge
➤
Proprietary AutoComp charge-rate compensation
➤
Integrated trickle-charge for conditioning deeply
discharged batteries
➤
Regulated charge current and voltage
➤
Charge status output for LED or host-processor
interface to indicate charge-in-progress,
full-capacity, and fault conditions
➤ Automatic battery-re-charge feature
➤ Charge termination by minimum current
➤ Direct battery connection
➤ 500mA charge rate
➤ High-side current sensing
General Description
The DV2057/C/T/W are complete development and
evaluation environments for bq2057 series advanced
Li-Ion linear charge management ICs. The DV2057 fam
-
ily supports both single- and dual-cell Li-Ion packs with
coke or graphite anodes:
Part Number Regulation Voltage
DV2057 4.1V
DV2057C 4.2V
DV2057T 8.2V
DV2057W 8.4V
Full charge is preceded by charge qualification based on
battery temperature and voltage. The DV2057/C/T/W
suspend charge if the battery temperature is outside the
V
TS1
to V
TS2
thresholds and wait until the battery tem
-
perature is within the allowed range. The
DV2057/C/T/W also check the battery voltage. If the bat
-
tery voltage is below the low-voltage threshold, V
MIN,
the
DV2057/C/T/W use trickle charge to condition the bat
-
tery. The conditioning charge rate, I
COND
, is set at
approximately 10% of the regulation current. The condi
-
tioning current also minimizes heat dissipation in the
external pass element during the initial stage of charge.
Once the battery voltage reaches the internal threshold,
V
MIN
, full charge begins. The DV2057/C/T/W complete
the charge cycle in two phases. While the pack is below
the regulation voltage, a constant-current phase replen-
ishes approximately 70% of battery capacity. An accu-
rate voltage-regulation phase completes the charge. The
DV2057/C/T/W terminate charge when the current ta-
pers off to the V
TERM
threshold.
These boards feature the proprietary AutoComp tech-
nique to compensate safely for the internal impedance of
the battery. The AutoComp resistors, R
COMP1
, and
R
COMP2
, must be set according to the characteristics of
the battery.
Before using these development boards, please review
the bq2057 data sheet.
Connection Descriptions
J1
DC+ Charger supply positive
DC- Charger supply ground
J2
BAT+ Positive battery terminal
BAT- Negative battery terminal
J3
TEM+ Thermistor connection
INH Charge inhibit input
1
DV2057/C/T/W
SLUU056A - JANUARY 2000
Advanced Li-Ion Charger Development System
Control of On-Board Linear Regulator