MAXIM MAX745EVKIT

19-1182; Rev 2; 12/98
MAX745 Evaluation Kit
The MAX745 evaluation kit (EV kit) is an assembled and
tested PC board that implements a step-down, switching power supply designed for charging lithium-ion (LiIon) batteries. The output voltage can be set for one to
four cells. The cell voltage can be set between 4.0V
and 4.4V, with 0.75% accuracy, using standard 1%
resistors. Two LEDs indicate the charging status.
The MAX745 should be used to charge only Li-Ion battery packs. To charge other types of batteries, use the
MAX1648 or the MAX712/MAX713. To charge SMBus™
smart-battery packs, use the MAX1647.
______________Component Suppliers
SUPPLIER*
AVX
Dale-Vishay
International Rectifier
IRC
Motorola
Sanyo
Sumida
PHONE
FAX
(803) 946-0690
(402) 564-3131
(310) 322-3331
(512) 992-7900
(602) 303-5454
(619) 661-6835
(847) 956-0666
(803) 626-3123
(402) 563-6418
(310) 322-3332
(512) 992-3377
(602) 994-6430
(619) 661-1055
(847) 956-0702
____________________________Features
♦ Charges One to Four Li-Ion Cells
♦ Low Heat/High Efficiency
♦ 300kHz PWM Operation
♦ 0.75% Overall Accuracy over Temperature
♦ 6V to 24V Input Voltage Range
♦ Proven PC Board Layout
♦ Fully Assembled and Tested
______________Ordering Information
PART
MAX745EVKIT
TEMP. RANGE
0°C to +70°C
BOARD TYPE
Surface Mount
*Please indicate that you are using the MAX745 when contacting these component suppliers.
_____________________________________________________________Component List
DESIGNATION QTY
C1
1
DESCRIPTION
68µF, 20V, 0.150Ω, low-ESR
tantalum capacitor
AVX TPSE686M020R0150
C2, C7, C9,
C12
4
0.1µF ceramic capacitors
C3
1
47nF ceramic capacitor
C4
1
0.22µF ceramic capacitor
C5
1
4.7µF, 10V, low-ESR capacitor
C6
0
Open
C8, C10
2
150µF, 35V, 0.17Ω, aluminum
electrolytic capacitors
Sanyo 35CV150GX
C11
1
1000pF ceramic capacitor
3
3A, 40V, surface-mount
Schottky diodes
Motorola MBRS340T3
D1, D4, D6
DESIGNATION QTY
DESCRIPTION
L1
1
22µH, 2.8A surface-mount inductor
Sumida CDRH125-220
LED1, LED2
2
Light-emitting diodes
M1
1
2A, 30V, 0.080Ω, logic-level, dual,
N-channel FET
International Rectifier IRF7303
R1
1
0.100Ω, 1% sense resistor
Dale WSL-2010-R1F or
IRC LR2010-01-R100F
R2, R15
2
10kΩ, 5%, surface-mount resistors
R3, R11, R12,
R16
4
100kΩ, 1%, surface-mount resistors
R4, R5, R10
0
Shorted
R6, R7
2
1kΩ, 5%, surface-mount resistors
R13
1
8kΩ, 5%, surface-mount resistor
R14
1
24Ω, 5%, surface-mount resistor
D2
1
1N4148-type signal diode (SOT23)
U1
1
Maxim MAX745EAP
J3, J4
2
Banana jacks
U2
1
Maxim MAX931CSA
None
1
Printed circuit board
JU1, JU2, JU3
3
3-pin headers
JU4
1
2-pin header
SMBus is a trademark of Intel Corp.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Evaluates: MAX745
_______________General Description
Evaluates: MAX745
MAX745 Evaluation Kit
_________________________Quick Start
_______________Detailed Description
Do not turn on power until all connections are complete. Observe all precautions on the battery manufacturer’s data sheet. Use only lithium-ion (Li-Ion)
cells with this charger.
1) Set jumpers JU1 and JU2 to indicate the number of
cells in the battery pack (Table 1).
Upon insertion, batteries are fast charged at a constant
current. Batteries enter float charge when the total battery terminal voltage reaches the voltage limit.
2) Set jumper JU3 to the 2A position to enable 2A output current (Table 2).
3) Make sure that jumper JU4 is open to enable charger output.
4) Connect a DC power supply with sufficient power
rating across the VIN and GND banana jacks (VIN
is positive, GND is negative). DC input voltage
should be between 6V and 24V.
5) Connect a Li-Ion battery pack between BATT and
GND (BATT is positive, GND is negative). The battery can be connected with the charger off without
causing damage, or it can be connected after
power is applied.
6) Turn on the DC power supply. Fast charging begins
as soon as the battery is connected and the DC
power supply is on.
7) When the STATUS LED turns on, the charger is
operating in current-regulating mode (fast charge).
When the STATUS LED turns off, the charger is
operating in voltage-regulating mode (float charge).
8) When the DONE LED turns on, the charging current
has fallen below the threshold set by R13, indicating that charging is over. The charger can be shut
down by closing jumper JU4.
LED2 (STATUS) indicates that the charger is in currentregulating mode. This signal can be used to detect the
transition from fast charge to float charge.
LED1 (DONE) indicates that the battery current (fast
charge) is below the threshold set by R13. The IBAT
output pin sources a current that is proportional to the
load current, and comparator U2 detects when that
load current exceeds the threshold set by R13. R13
should not cause the IBAT voltage to exceed 2V under
maximum load current. See the MAX745 data sheet.
Table 2. Jumper Functions
JUMPER
STATE
JU1
3, 4
CELL1 = VL; three or four cells selected.
JU1
1, 2
CELL1 = GND; one or two cells selected.
JU2
2, 4
CELL0 = VL; two or four cells selected.
JU2
1, 3
CELL0 = GND; one or three cells selected.
JU3
2A
ISET = REF; output current limited to 2A.
JU3
Open
ISET is open; output current limited to 1A.
JU3
0A
JU4
Open
JU4
FUNCTION
ISET = GND; output current disabled.
THM = REF; output enabled.
Closed THM = GND; output disabled.
Table 1. Configuring Number of
Lithium-Ion Cells
2
NUMBER OF
CELLS
VOLTAGE
ADJUSTMENT
RANGE
JU1
POSITION
JU2
POSITION
1
4V-4.4V
1, 2
1, 3
2
8V-8.8V
1, 2
2, 4
3
12V-13.2V
3, 4
1, 3
4
16V-17.6V
3, 4
2, 4
_______________________________________________________________________________________
JU4
R15
10k
REF
C5
4.7µF
10V
C6
OPEN
R11
100k
1%
R3
100k
1%
VL
6
5
4
C12
0.1µF
C9
0.1µF
REF
HYST
IN-
IN+
JU3
0A
1A
2A
R2
C2 10k
0.1µF
REF
R13
8k
IBAT 3
R12
100k
1%
R16
100k
1%
6
5
4
3
2
1
10
9
1
8
GND
SETI
VADJ
REF
U1
R7
1k
VL
JU2
1, 3
2, 4
VL
MAX745
THM/SHDN
CCI
CCV
VL
DCIN
IBAT
GND
OUT
7
C4
0.22µF
8
C3
47nF
DCIN
2
V-
MAX931
U2
V+
7
JU1
11
12
13
14
15
16
17
18
19
1, 2
3, 4
VL
CELL1
CELLO
STATUS
BATT
CS
PGND
DLO
DHI
LX
20
D2
LED1
DONE
BST
R14
24Ω
VL
C7
0.1µF
GND
VIN
VL
7
R6
1k
LED2
STATUS
PGND
2
R5
SHORT
R4
SHORT
R10
SHORT
DCIN
PGND
J4
BLACK
J3
RED
4
3
1
M1A
8
5
D4
D1
M1B
6
L1
22µH
PGND
D6
C8
150µF
35V
C11
1000pF
R1
0.1Ω
1%
PGND
PGND
C10
150µF
35V
BATT-
C1
68µF
20V
BATT+
Evaluates: MAX745
VL
MAX745 Evaluation Kit
Figure 1. MAX745 EV Kit Schematic Diagram
_______________________________________________________________________________________
3
Evaluates: MAX745
MAX745 Evaluation Kit
1.0"
1.0"
Figure 2. MAX745 EV Kit Component Placement Guide—
Component Side
Figure 3. MAX745 EV Kit PC Board Layout—Component Side
1.0"
Figure 4. MAX745 EV Kit PC Board Layout—Solder Side
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
4 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1998 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.