MAXIM MAX1645EVKIT

19-1596; Rev 0; 3/00
MAX1645 Evaluation System
The MAX1645 evaluation system (EV system) consists of
a MAX1645 evaluation kit (EV kit) and a companion
Maxim System Management Bus (SMBus™) interface
board. The EV kit simplifies evaluation of the MAX1645
chemistry-independent Level 2 smart battery charger.
The Maxim SMBus interface board (MAXSMBus) allows
an IBM-compatible personal computer to use its parallel port to emulate an Intel SMBus 2-wire interface.
Windows 95/98® software provides a user-friendly interface to exercise the MAX1645’s features.
Order the MAX1645EVSYS for complete IBM PC-based
evaluation of the MAX1645. Order the MAX1645EVKIT if
you already have an SMBus interface.
Features
♦ Charges Any Battery Chemistry: Li-Ion, NiCd,
NiMH, Lead Acid, etc.
♦ SMBus-Compatible 2-Wire Serial Interface
♦ 3A max Battery Charge Current
♦ Up to 18.4V Battery Voltage
♦ Up to +28V Input Voltage
♦ Easy-to-Use Software Included
♦ Proven PC Board Layout
♦ Fully Assembled and Tested Surface-Mount Board
EV System
Component List
Ordering Information
PART
TEMP. RANGE
None
1
MAX1645 EV kit
MAX1645EVKIT
0°C to +70°C
28 QSOP
None
1
MAXSMBus interface
MAX1645EVSYS
0°C to +70°C
28 QSOP
DESIGNATION QTY
DESCRIPTION
IC PACKAGE
EV Kit Component List
DESIGNATION QTY
DESCRIPTION
DESIGNATION QTY
DESCRIPTION
22µF, 35V low-ESR tantalum caps
AVX TPSE226M035R0300
H1
1
2x10 right-angle female header
H2
1
5-element terminal block
2
22µF, 25V low-ESR tantalum caps
AVX TPSD226M025R0200
JU1, JU2, JU3
3
2-pin headers
L1
1
3
1µF, 50V ceramic capacitors (1210)
Murata GRM42-2X7R105K050
22µH, 3.6A inductor
Sumida CDRH127-220
LED1
1
Red LED
C6, C7, C12
3
1µF, 10V ceramic capacitors (0805)
Taiyo Yuden LMK212BJ105MG
N1
1
30V, 11.5A N-channel MOSFET
Fairchild FDS6680
C8, C14, C15,
C16
4
0.1µF, 16V ceramic capacitors (0603)
Taiyo Yuden EMK107BJ104MA
N2
1
30V, 8.4A N-channel MOSFET
Fairchild FDS6612A
C9, C10, C11
3
0.01µF ceramic capacitors (0603)
C13
1
1500pF ceramic capacitor (0603)
P1, P2
2
30V, 11A P-channel MOSFETs
Fairchild FDS6675
C18, C23, C24
3
0.1µF, 50V ceramic capacitors (0805)
Taiyo Yuden UMK212BJ104MG
R1
1
0.040Ω ±1%, 0.5W resistor
Dale WSL-2010/0.040Ω/1%
D1, D2
2
40V, 2A Schottky diodes
Central Semiconductor CMSH2-40
R2
1
0.050Ω ±1%, 0.5W resistor
Dale WSL-2010/0.050Ω/1%
D3, D4
2
Schottky diodes (SOT23)
Central Semiconductor CMPSH-3
C1, C2
C3, C4
C5, C19, C20
2
R3, R4
2
100kΩ ±1% resistors (0603)
R5, R7, R9,
R10, R17
5
10kΩ ±5% resistors (0603)
R6
1
10kΩ ±1% resistor (0603)
SMBus is a registered trademark of Intel Corp.
Windows 95/98 are registered trademarks of Microsoft Corp.
________________________________________________________________ Maxim Integrated Products
1
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Evaluates: MAX1645
General Description
Evaluates: MAX1645
MAX1645 Evaluation System
EV Kit Component List (cont.)
DESIGNATION QTY
DESCRIPTION
R8, R13
2
1kΩ ±5% resistors (0603)
R11, R16
2
1Ω ±5% resistors (0603)
R12
1
33Ω ±5% resistor (0603)
R14, R15
2
4.7Ω ±5% resistors (0603)
Table 1. Jumper Functions
JUMPER
Closed*
SCL pulled up to VDD through
a 10kΩ resistor.
U1
1
MAX1645EEI (28-pin QSOP)
3
Shunts (JU1, JU2, JU3)
None
1
MAX1645 PC board
None
1
MAX1645 data sheet
None
1
MAX1645 EV kit data sheet
None
1
MAX1645 EV kit software disk
Open
Closed*
JU2
Open
Closed*
Component Suppliers
PHONE
FAX
AVX
803-946-0690
803-626-3123
Central
Semiconductor
516-435-1110
516-435-1824
Dale
402-564-3131
402-563-6418
Fairchild
408-822-2000
408-822-2102
Murata
814-237-1431
814-238-0490
Sumida
847-956-0666
847-956-0702
Taiyo Yuden
408-573-4150
408-573-4159
JU3
Open
SCL not pulled up to VDD;
SCL must be pulled up to
external supply.
SDA pulled up to VDD through
a 10kΩ resistor.
SDA not pulled up to VDD;
SDA must be pulled up to
external supply.
10kΩ resistor connected
between thermistor and ground
nodes, simulating the attachment of a smart battery.
10kΩ resistor disconnected;
for use when an actual smart
battery will be connected to
the EV kit.
*Indicates default jumper setting
Note: Please indicate that you are using the MAX1645 when
contacting the above component suppliers.
Quick Start
Required Equipment
Before you begin, you will need the following equipment:
• IBM PC-compatible computer capable of running
Windows 95/98
• Parallel printer port (this is a 25-pin socket on the
back of the computer)
• Standard 25-pin, straight-through, male-to-female
cable to connect the computer’s parallel port to the
Maxim SMBus interface board
• DC power supply capable of supplying +20V to
+28V at 3A
2
FUNCTION
JU1
None
SUPPLIER
STATE
Procedure
See Figure 1 as you follow these steps:
1) Carefully connect the boards by aligning the 20-pin
connector of the MAX1645 EV kit with the 20-pin
header of the MAXSMBus interface board. Gently
press them together. The two boards should be flush
against each other.
2) Verify that jumpers JU1, JU2, and JU3 are all
shunted. JU1 and JU2 pull up the SMBus clock and
data lines to the VDD supply. JU3 connects a 10kΩ
resistor between the ground and thermistor nodes,
making it appear to the MAX1645 as if a smart battery
were connected. Table 1 describes the jumper functions.
Caution: Do not turn on the power until all connections are made.
3) Connect a +20VDC to +28VDC power supply
between the VIN pad and the adjacent GND pad on
the MAX1645 EV kit board.
4) Connect a cable from the computer’s parallel port to
the SMBus interface board. Use a straight-through,
25-pin, female-to-male cable. To avoid damaging the
EV kit or your computer, do not use a 25-pin SCSI
port or any other connector that is physically similar
to the 25-pin parallel printer port.
Note: Do not connect a power supply to the
MAXSMBus board. Power is supplied through the
MAX1645 EV kit board.
_______________________________________________________________________________________
MAX1645 Evaluation System
Evaluates: MAX1645
TO PC
PARALLEL PORT
DC POWER SUPPLY
MAXSMBus
-
+
GND
VIN
MAX1645 EVALUATION KIT
LOAD
VL
DB-25M
REF
JU1
BATT
JU2
JU3
GND
LED1
(+) C
D
T
(-)
(+) C
D
S
(-)
SMART BATTERY
Figure 1. Block Diagram of MAX1645 EV System
_______________________________________________________________________________________
3
Evaluates: MAX1645
MAX1645 Evaluation System
5) Install the MAX1645 EV kit software on your computer by running the INSTALL.EXE program on the floppy disk. This program copies the MAX1645 program
file and creates an icon for it.
6) Turn on the power supply. Verify that LED1 turns on.
7) Start the MAX1645 program by opening its icon in
the START MENU. The EV kit software automatically
detects the correct port by testing for the pin 5 to pin
13 loopback. Verify that LED1 turns off, signifying
that communication between the PC and the
MAX1645 has been established.
8) The software should appear as shown in Figure 2.
Verify that Charging Voltage = 65535mV, Charging
Current = 128mA; HOT_STOP is checked; Voltage
Polling, Current Polling, and Status Polling are
checked; and the following checkboxes are checked
in the Charger Status panel: VOLTAGE_NOTREG,
VOLTAGE_OR, BATTERY_PRESENT, and AC_PRESENT.
Detailed Description
of Software
Upon execution of the MAX1645 program, the software
automatically resolves the SMBus address of the
device. The software enables the command panel
(Figure 2), after which the user may issue any of the
allowed SMBus commands to the MAX1645. Refer to
the MAX1645 data sheet for more information regarding
the allowed SMBus commands.
Command Panel
ChargingVoltage()
To issue the ChargingVoltage() command to the
MAX1645, enter the desired voltage, in millivolts, into the
Charging Voltage text edit box and select the adjacent
[Send] button. By default, the software issues the
ChargingVoltage() command three times a second. To
enable/disable this feature, check/uncheck the Voltage
Polling checkbox. If a smart battery is connected to the
charger, the Charging Voltage value displayed will be
identical to the value being broadcast by the smart battery.
ChargingCurrent()
To issue the ChargingCurrent() command to the
MAX1645, enter the desired current, in milliamps, into
the Charging Current text edit box and select the adjacent [Send] button. By default, the software issues the
ChargingCurrent() command three times a second. To
Figure 2. MAX1645 EV Kit Software Command Panel
4
_______________________________________________________________________________________
MAX1645 Evaluation System
The Alert Response operation works as follows: the
SMBus specification revision 1.0 describes an optional
wired-or signal called SMBALERT that, in a typical system, is connected to all the devices and then pulled up
to VDD. A SLAVE device can use this signal to notify the
bus MASTER that it wants to communicate. It does this
by pulling the SMBALERT line LOW. When the MASTER
sees the SMBALERT line go LOW, it knows that one of
the SLAVE devices wants attention, but not which one.
To determine which SLAVE pulled the SMBALERT line
LOW, the MASTER broadcasts the Alert Response
Address (0x18) to all of the SLAVE devices on the bus
using a modified RECEIVE BYTE operation. The SLAVE
device wanting to communicate with the MASTER
responds with its SMBus address (0x13) during the
second byte of the modified RECEIVE BYTE operation.
ChargerMode()
To issue the ChargerMode() command to the MAX1645,
select a combination of checkboxes in the Charger
Mode panel of commands. Check the checkboxes next
to commands for which the software should write a 1,
uncheck the checkboxes next to commands for which
the software should write a 0, and then select the [Send]
button.
AlarmWarning()
To issue the AlarmWarning() command to the
MAX1645, select the [Alarm Warning] button. This
operation sends the AlarmWarning() command byte
with a data word of 0x8000.
ChargerStatus()
On the right-hand side of the command panel, locate
the Status Polling checkbox and the Charger Status
panel. If the Status Polling checkbox is checked (the
default setting), the software automatically issues the
ChargerStatus() command three times a second, in
which case the checkboxes in the Charger Status
panel are automatically updated and always represent
the charger’s current status. Unchecking the Status
Polling checkbox disables automatic software polling.
If polling is disabled, the user can issue the
ChargerStatus() command to the MAX1645 by selecting the [Charger Status] button, which is adjacent to
the Status Polling checkbox.
AlertResponse()
The MAX1645 has an external interrupt pin that is
polled by the software if the Status Polling checkbox is
checked. When an interrupt occurs, LED1 on the EV kit
board illuminates. If polling is enabled, the software
determines which event triggered the interrupt, clears
the interrupt, and prints a diagnostic message in the
Interrupts box. If polling is disabled and an interrupt
occurs, the user can manually service the interrupt by
selecting the [Alert Response] button.
ChargerSpecInfo()
To issue the ChargerSpecInfo() command to the
MAX1645, select the [Spec Info] button. The response
of the MAX1645 is displayed to the right of the [Spec
Info] button.
Communication with a Smart Battery
If a smart battery is connected to the MAX1645 EV kit,
the user may observe the status of the smart battery by
selecting the [Battery] button. At this point, the smart
battery window appears (Figure 3). If software polling
of the charger’s status is enabled, the software also
Figure 3. MAX1645 EV Kit Smart Battery Window
_______________________________________________________________________________________
5
Evaluates: MAX1645
enable/disable this feature, check/uncheck the Current
Polling checkbox. If a smart battery is connected to the
charger, the Charging Current value displayed will be
identical to the value being broadcast by the smart battery.
Note that when either Voltage Polling or Current
Polling are checked, the action of issuing the
ChargingVoltage() or ChargingCurrent() commands
automatically services the watchdog timer. If both of
these checkboxes are unchecked, the watchdog timer
will eventually time out and charging will stop. For more
information about the watchdog timer, refer to the
MAX1645 data sheet. If the watchdog timer period of
175s is exceeded, reset the watchdog timer by issuing
both the ChargingVoltage() and ChargingCurrent()
commands.
Evaluates: MAX1645
MAX1645 Evaluation System
automatically polls the status of the smart battery, and
the parameters displayed in the smart battery window
always represent the current status of the smart battery.
If polling is disabled, manually query the smart battery
by selecting the [Update] button. When finished, select
the [Done] button to return to the main MAX1645 user
interface window.
Serial Communications Interface
When the user issues a command, the MAX1645 software first determines the command byte, then, if the
command is a Write-Word type, the data word corresponding to the selected function. The software and
MAX1645 device communicate serially through the
MAXSMBus board. Refer to the MAX1645 data sheet
for more information regarding the serial communications protocol.
Detailed Description
of Hardware
Input Current Limiting
The MAX1645 EV kit is configured to regulate the battery
current so that the total V IN input current does not
exceed 2.5A. If a load is connected across the LOAD
and GND pads (another system power supply, for
example) that would cause the total current from VIN to
exceed 2.5A, the MAX1645 will automatically decrease
its charging current to regulate the input current to
2.5A. Refer to the MAX1645 data sheet for more information regarding input current limiting.
Connecting an Electronic Load
If a smart battery is unavailable, an electronic load can
be connected across the BATT and GND pads on the
MAX1645 EV kit board. Make sure that the EV kit power
is turned off before connecting a load. Make sure that
JU3 is shunted, making it appear to the MAX1645 as if
a smart battery were connected. After the load is connected, program the load in voltage mode and set the
electronic load to clamp at 5V. Turn on the power to the
EV kit, and program the MAX1645 with a charging voltage
of 12V at the maximum charging current. Verify that the
MAX1645 is supplying the maximum current to the
load. Increase the electronic load clamp voltage in 1V
increments, and verify that as the electronic load voltage
crosses 12V, the MAX1645 transitions from current regulation to voltage regulation; as the electronic load voltage
increases beyond 12V, the BATT voltage should remain
fixed at 12V.
Layout Considerations
The MAX1645 EV kit layout is optimized for fast switching
and high currents. The traces connecting the power
components must be able to carry at least 3A. Take
care to ensure that C1 and C2 (the input capacitors),
D2 and N2 (the synchronous rectifier), and C3 and C4
(the output capacitors) are all connected to GND at a
common point, and to isolate the power GND from the
quiet analog GND.
Connecting a Smart Battery
The MAX1645 EV kit includes a five-element terminal
block to facilitate connecting the EV kit to a smart battery.
Refer to the smart battery specification to identify the
type of smart battery connector suited to your application.
Make sure that the EV kit power is turned off, and connect
the (+), C, D, T, and (-) terminals from the EV kit board
to the smart battery connector using no more than 2
inches of wire. Remove the JU3 shunt, attach a smart
battery to the smart battery connector, and turn the EV
kit power back on. See Figure 1 if necessary.
6
_______________________________________________________________________________________
MAX1645 Evaluation System
LDO
2
LDO
C6
1µF
8
1
DCIN
LDO
C23
0.1µF
50V
GND
C7
1µF
U1
R3
100k
1%
C15
0.1µF
3
CLS
10
DAC
R4
C8
100k
1% 0.1µF
R5
10k
C9
0.01µF
7
6
C10
0.01µF
5
C11
0.01µF
H1-1
H1-2
11
C12 R6
1µF 10k
1%
C13
1500pF
H1-4
12
R7
10k
H1-5
REF
MAX1645
P1
R14
4.7Ω
28
CVS
27
PDS
26
CSSP
CSSN
4
REF
= 3A TRACES
VIN
R13
1k
BST
C20
1µF
50V
25
DLOV
C14
0.1µF
N1
CSIP
CCS
CSIN
SCL
13
R12
33Ω
LDO
C16
0.1µF
N2
D2
L1
22µH
R11
1Ω
18
C18
0.1µF
50V
17
R16
1Ω
C24
0.1µF
50V
VDD
THM
INT
15
C2
22µF
35V
D3
21
PGND 19
CCI
C1
22µF
35V
22
DLO 20
CCV
R1
0.040Ω
1%
1/2W
R15
4.7Ω
C19
1µF 50V
24
DHI 23
LX
D1
PDL 16
9
BATT
SDA
14
R2
0.050Ω
1%
1/2W
LOAD
LOAD
P2
C3
22µF
25V
BATT
C4
22µF
25V
H1-6
H1-3
H1-7
JU3
LOAD
H1-20
R17
10k
R8
1k
JU1
JU2
GND
LED1
H2
R9
10k
GND
(+)
C
D
T
(-)
R10
10k
Figure 4. MAX1645 EV Kit Schematic
_______________________________________________________________________________________
7
Evaluates: MAX1645
D4
C5
1µF
50V
Evaluates: MAX1645
MAX1645 Evaluation System
1.0"
Figure 5. MAX1645 EV Kit Component Placement Guide—
Component Side
1.0"
Figure 7. MAX1645 EV Kit PC Board Layout—Component Side
8
1.0"
Figure 6. MAX1645 EV Kit Component Placement Guide—
Solder Side
1.0"
Figure 8. MAX1645 EV Kit PC Board Layout—Solder Side
_______________________________________________________________________________________