TI DV2057 Advanced li-ion charger development system control of on-board linear regulator Datasheet

DV2057/C/T/W
Advanced Li-Ion Charger Development System
Control of On-Board Linear Regulator
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
approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the
external pass element during the initial stage of charge.
➤
Automatic battery-re-charge feature
➤
Charge termination by minimum current
➤
Direct battery connection
➤
500mA charge rate
➤
High-side current sensing
Once the battery voltage reaches the internal threshold,
VMIN, 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 replenishes approximately 70% of battery capacity. An accurate voltage-regulation phase completes the charge. The
DV2057/C/T/W terminate charge when the current tapers off to the VTERM threshold.
These boards feature the proprietary AutoComp technique to compensate safely for the internal impedance of
the battery. The AutoComp resistors, R COMP1 , and
RCOMP2, must be set according to the characteristics of
the battery.
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 family supports both single- and dual-cell Li-Ion packs with
coke or graphite anodes:
Part Number
DV2057
DV2057C
DV2057T
DV2057W
Before using these development boards, please review
the bq2057 data sheet.
Connection Descriptions
Regulation Voltage
4.1V
4.2V
8.2V
8.4V
J1
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
VTS1 to VTS2 thresholds and wait until the battery temp e r a t u r e i s w i t h i n t h e a l l o w e d r a n g e. T h e
DV2057/C/T/W also check the battery voltage. If the battery voltage is below the low-voltage threshold, VMIN, the
DV2057/C/T/W use trickle charge to condition the battery. The conditioning charge rate, I COND, is set at
DC+
Charger supply positive
DC-
Charger supply ground
BAT+
Positive battery terminal
BAT-
Negative battery terminal
TEM+
Thermistor connection
INH
Charge inhibit input
J2
J3
SLUU056A - JANUARY 2000
1
DV2057/C/T/W
Configuration
As configured, charge can be inhibited by connecting the
INH input to DC+ or DC–.
These boards have the following characteristics:
The value of R2 at shipment is 0.2Ω. This resistor can be
changed to suit the application. However, the maximum
power dissipation in Q1 should not exceed the PD rating. (See recommended DC Operating Conditions.)
DV2057/C/T/W Regulation Voltages
Part Number
Regulation Voltage
DV2057
DV2057C
DV2057T
DV2057W
Setup Procedure
4.1V
4.2V
8.2V
8.4V
■
Supply connector J1 accepts a maximum of 16VDC
(See the limitation on power dissipation below.)
■
Charge begins after application of both of the following:
–
the battery
–
supply voltage
■
Temperature sensing: disabled
■
AutoComp: disabled
Connect the battery pack to J1.
2.
Connect the charging supply to J2.
See the bq2057 data sheet for information on configuring the temperature sensing circuit and the AutoComp
feature.
As shipped the DV2057/C/T/W uses a bipolar transistor
(Q1). Optionally, the user may replace Q1 with a
P-channel MOSFET. Please refer to the schematic for
details.
The on-board regulator supplies a charging current of
500mA. This current is controlled by the value of the
sense-resistor, R2 in the following equation:
ICHG =
1.
0.100
R2
2
DV2057/C/T/W
DV2057/C/T/W Schematic
J1
1
2
Q1
FZT788B
R2
D1
DC+
DC-
0.2
ZHCS1000
J2
BAT+
C2
1µF
BAT-
1
2
3
R1
1.0k
R4
RCOMP2
1
RCOMP1
2
R3
2K
U1A
8
COMP SNS
7
CC
BAT
6
VCC
5 VSS
STAT
TS
D2
LED
1
2
3
4
RT1
J3
TEMP+
INH
1.5M
bq2057
SOIC
C1
0.1
RT2
1.5M
U1B
8
COMP SNS
7 CC
BAT
6
VCC
VSS
5
STAT
TS
bq2057
TSSOP
Notes:
1
As shipped:
RCOMP1 = open circuit
RCOMP2 = 0Ω
2
Development Board
DV2057
DV2057C
DV2057T
DV2057W
3
For use with a bipolar transistor: (Q1 is FZT788B)
R1 = 1.0kΩ
R4 = open circuit
For use with a MOSFET: (Q1 is BSP171P (Infineon))
R1 = 100Ω
R4 = 1.0kΩ
4.
ZHCS1000 and FZT788B are made by Zetex, Inc.
Part Number
bq2057SN or bq2057TS
bq2057CSN or bq2057CTS
bq2057TSN or bq2057TTS
bq2057WSN or bq2057WTS
3
1
2
3
4
2
1
2
DV2057/C/T/W
Recommended DC Operating Conditions
Symbol
Description
Minimum
Typical
Maximum
Unit
Notes
VDC
Input DC voltage
VBAT +0.5
-
15
V
See Note.
ICHG
Battery charge current
-
-
500
mA
See Note.
VTHERM
Therm input voltage
0
-
VDC
V
VINH
Inhibit input voltage
0
-
VDC
V
0
See Regulation
Voltages Table.
VDC
V
1.75
W
VBAT
BAT input voltage
PD
Power dissipation
Note: Power dissipation must not exceed the maximum PD rating.
PD = ICHG ∗ (VDC - VBAT)
4
At 40°C ambient
temperature
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