an1857

Application Note 1857
ISL94208EVZ (Rev B) User Guide
Introduction
This document is intended for use by individuals engaged in
the development of hardware for a 4- to 6- series connected
Li-ion battery pack using the ISL94208EVZ board.
The evaluation kit provides full battery pack operation as well
as offering the ability to read and write the ISL94208 registers,
set thresholds and timer values, read cell voltages, control cell
balancing outputs, and control the power FETs.
The kit contains the following components:
• ISL94208EVZ board.
• ISL94208DB1EVZ cell balance daughter board.
• ISL94208DB2EVZ cell balance daughter board.
• GUI software for a PC running Windows XP.
• A power supply interface board for connecting a single
power source or a battery stack.
Operation of the ISL94208EVZ board requires the use of a
separate USB to I2C kit, part number “ISLI2C-KIT”.
An optional link between the PC and the microcontroller BKGD
connector is available from NXP (formerly Freescale) for
monitoring and debugging the microcontroller code.
Board Software” on page 10. For this use, a License
agreement is not needed.
• Set up a power supply for the board. The power supply
should consist of a string of 4 to 6 batteries (see Figure 2), or
a string of 4 to 6 resistors and a power supply, or 4 to 6
individual power supplies (see Figures 2, 3).
To facilitate the power connections, the kit includes a
power supply board.
First Steps
• If not already available, acquire the DeVaSys USB to I2C
interface cable and module. This is available from Intersil in
the ISLI2C-KIT.
• Download the software from the Intersil website on the
ISL94208 page. This is a zip file titled: “ISL94208EVZ Kit
Software Release V2.10”.
• Unzip the software files to a directory of your choice.
• Prior to powering the ISL94208 (Rev B) board, install the
USB to I2C board software and connect the DeVaSys board
to the PC (see Appendix 1). However, do not connect the
DeVaSys board to the ISL94208EVZ board, yet. This is just
preparation of the test set up. With these pieces in place,
the PC interface can then quickly be used to monitor the
operation of the board, once power is applied.
• If changes to the microcontroller code are desired, then it
will be necessary to order a programming/debug module
from NXP (formerly Freescale), part number,
USBMULTILINKBDME. This kit also contains the Code
Warrior development tools. To get the source code, contact
Intersil and sign the license agreement. The
programming/debug module is needed if the board is going
to be calibrated. See “Installing The DeVaSys USB to I2C
September 17, 2013
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FIGURE 1. ISL94208EVZ KIT BOARDS
1
The kit operates without using either cell balance board,
however, if cell balancing is desired, then one of the two
daughter boards should be connected before powering the
board.
Battery/Power Supply
Connection
When connecting battery packs or power supplies, use the
recommended connections as shown in Figure 2. Make sure
that the individual power supply voltages do not exceed the
ISL94208 maximum input voltage differential of 5V per cell.
If using a string of resistors to emulate the battery cells, then
limit the power supply voltage, so that the resistor divider
outputs do not exceed the ISL94208 input maximum ratings.
It is recommended that, when using the resistor divider circuit
(see Figure 2), the series resistors to be 100 or less and 2W
minimum and balancing be disabled. Balancing should be
disabled, because when activating the ISL94208 cell balance
outputs, the current balance on the ISL94208 (Rev B) board
lowers the voltage across balanced power supply resistor,
while raising the voltage on all of the other series resistors.
Turning on multiple cell balance outputs could then result in
one or more of the VCELLN input voltages exceeding their
maximum specified limit.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2013. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
Application Note 1857
6 CELLS
6 POWER SUPPLIES
VCC
VCC
7
VCELL6
6
CB6
VCELL5
V
5
CB5
VCELL4
V
4
CB4
VCELL3
V
3
CB3
VCELL2
2
1
VCC
7
VCELL6
4 CELLS
VCC
VCC
7
VCELL6
7
VCELL6
VCELL6
6
CB6
VCELL5
6
CB6
VCELL5
6
CB6
VCELL5
5
CB5
VCELL4
5
CB5
VCELL4
5
CB5
VCELL4
4
CB4
VCELL3
4
CB4
VCELL3
4
CB4
VCELL3
CB3
VCELL2
3
CB3
VCELL2
3
CB3
VCELL2
3
CB3
VCELL2
2
CB2
VCELL1
2
CB2
VCELL1
2
CB2
VCELL1
2
CB2
VCELL1
1
CB1
VCELL0
VSS
1
CB1
VCELL0
VSS
1
CB1
VCELL0
VSS
1
CB1
VCELL0
VSS
6
CB6
VCELL5
5
CB5
VCELL4
4
CB4
VCELL3
V
3
CB2
VCELL1
V
CB1
VCELL0
VSS
V
15V-27V
7
5 CELLS
6 SERIES RESISTORS
V
NOTES:
1. For the battery simulation resistors, use 100Ω/2W devices (maximum). If the divider resistors are more than 100Ω, then turning on the cell
balance output can cause fluctuations in the cell input voltages that can violate the ISL94208 max specifications. If the series resistors are larger
than 100Ω, we recommend removing the cell balance daughter board, to prevent accidental cell balancing, while monitoring the cell voltages
and pack operation.
2. Before connecting the power supply to the board, check the voltages at the connector to verify that they are correct.
3. Multiple battery cells can be connected in parallel.
FIGURE 2. BATTERY CONNECTION OPTIONS
B+/PACK+
OPTIONAL 5 CELL CONNECTION
6 CELL CONNECTION
TO LOAD +
OR CHARGER +
TO LOAD +
OR CHARGER +
CONNECTOR
MALE ON BOARD
(TOP VIEW)
BAT-
PACK-
CONNECTOR
MALE ON BOARD
(TOP VIEW)
TO
LOAD BAT-
CH-
OPTIONAL THERMISTOR
OR 50k POT (IF USED,
REMOVE THERMISTOR
ON BOARD)
TO
CHARGER -
CONNECT TOGETHER TO
ACTIVATE WAKE UP ON
CHARGE CONNECT CIRCUIT
PACK-
TO
LOAD -
CHTO
CHARGER -
FIGURE 3. BATTERY CELL CONNECTION TO ISL94208 PCB
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Application Note 1857
Initial Testing
USB to I2C interface
Setup
• Once the power supply connections are verified, make the PC
connection to the board, via the USB port, the DeVaSys board,
and the I2C cable. Before making this connection, make sure
that the USB to I2C interface software is installed (see
software installation guide).
• Figure 4 shows a green board is connects between a power
supply and the evaluation board. This multi-option board
supports the connection a single power supply (using an
on-board resistor divider), or separate power supplies for each
input, or battery cells.
• For this setup, connect a 20V supply to the power supply board
with GND on J8 or J12 and the positive connected to J5 or J11.
There should be a shunt on the “8-Cell” jumper. There is a
jumper wire on the power supply board connecting the CELL8
input to the CELL6 input to provide a 6-cell source.
• Before connecting the PC to the ISL94208EVZ board (through
the USB to I2C interface) turn off the power supply and then
plug the ISL94208EVZ board into the power supply board as
shown in Figure 4.
• Turn on the power supply.
• Once power is turned on (or Li-ion cells are connected to the
ISL94208 (Rev B) board), the Green RGO LED should light. Use
meter 1 to measure the RGO voltage. It should read about 3.3V.
• Connect the I2C cable from the DeVaSys board to the
ISL94208EVZ board as shown in Figure 5. Use the 5- to 4-pin
cable provided in the ISLI2C-KIT.
CAUTION: The I2C interface ground pin connects with the
Battery negative terminal. If a load connected between the
Pack + and Pack - pins has the same ground reference as the
PC, then both sides of the power FETs will be connected
together through the PC and load ground leads. The Power
FETs provide no interruption in the power path. Also, without
proper care, there can be problems with ground loops or
excess voltage conditions as a result of this connection. If the
ground connections are a concern, see “I2C Isolation” on
page 9.
TO PC:
RGO (ISL94208)
DEVASYS:
USB to I2C
METER 1
AO (ISL94208)
(3.3V)
15V-27V BATTERY/POWER SUPPLY
I2C CONNECT
Meter 2
(0-2.3V)
BKGD CONNECT
GND
TO PC:
JUMPER ON “8
CELL”POSITION
NXP
(FORMERLY
FREESCALE)
USB LINK
USB to BKGD
(OPTIONAL)
POWER SUPPLY BOARD
PROVIDES RESISTOR DIVIDER
FOR GENERATING CELL
VOLTAGES.
USBLINK:
USB to BKGD
(Optional)
FIGURE 4. ISL94208EVZ EVALUATION BOARD TEST CONNECTION
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Application Note 1857
The microcontroller on the board performs in a number of
automatic functions. These are as follows:
.
ISL94208EVZ
J8
SDA
GND
GND
SCL
FETs
CABLE
J29 5-PIN TO 5-PIN
DeVaSys BOARD
J2
1
1
USE 5-PIN TO
4-PIN CONNECTOR
SUPPLIED WITH ISLI2C-KIT
USB
FIGURE 5. I 2C CONNECTION TO ISL94208 PCB
1. The cell inputs are monitored to high or low voltage. If any of
the cell voltages go to high, the charge FET is turned off. If any
of the cell voltages go to low, the discharge FET turns off.
When voltage recovers from these excursions, back into the
normal range, the FETs automatically turn on.
2. After an overcurrent or undervoltage condition, the
microcontroller monitors the load and turns the FETs back on
when the load is released.
3. The microcontroller monitors the temperature and turns off the
cell balance and power FETs if temperature is to high or low.
Testing the Board
4. The microcontroller performs cell balancing (once it is
enabled through the GUI).
• Power-up the board and start the GUI. The PC will be
communicating with the microcontroller and the
microcontroller will be communicating with the ISL94208.
5. The microcontroller monitors the cell voltages and reports
these voltages to the GUI.
• The GUI should power-up with some color. In this case, the FET
controls should be GREEN and the indicators should all be
green. If the GUI is all gray, then there is a communication
problem (see the troubleshooting guide in the Appendix).
• If the FET indicators remain RED after power-up, it is likely that
at least one input voltage or the temperature is out of range.
In normal operation, the cell voltages are scanned four times per
second. If monitoring the AO voltage (as shown in Figure 4), the
meter will not be stable, since it sees an output of a series of
voltages. A scope can be used to monitor the AO output, or use
the GUI to select a specific voltage or temperature. This operation
by the GUI stops the microcontroller from automatically scanning
the voltages and puts the selected voltage on AO constantly.
Automatic scanning will not start again until the GUI selects
Monitor “All” (see Figure 6).
SELECT THE VOLTAGE TO MONITOR
OR SELECT ALL.
SELECT ALL TO START AUTO SCAN.
FIGURE 6. ISL94208 GUI MONITOR TAB
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Application Note 1857
Over/UnderVoltage Testing
• Test the overvoltage and undervoltage conditions by any of the
following means. Monitoring the FET status using GUI, then a
status update is required for the GUI to acquire the FET state.
Setting an autoscan in the GUI is a quick way to check FET
status. You can also use a meter to detect whether the
ISL94208 is driving the FET gate or not.
–If Li-ion cells are being used, discharge the pack until one
or more of the cells reach undervoltage limit and the
discharge FET turns off. Then, charge the pack until the
FETs turn on again and continue charging until a cell
overvoltage condition is reached.
–If one power supply is being used, lower the voltage on
power supply until one or more of the cells reach
undervoltage limit and the discharge FET turns off. Then,
increase the voltage until the FETs turn on again and
continue increasing the voltage until a cell overvoltage
condition is reached.
–If seven power supplies are used, then simply decrease or
increase any individual supply until the thresholds are
reached and the FET turns off (or on).
Overcurrent Testing
• Testing the overcurrent settings with the ISL94208EVZ board
is not easy without changing the values of the sense resistors
on the board, because it was designed as a possible reference
application.
• As delivered, the ISL94208EVZ board provides a discharge
sense resistor of 2.5mΩ and a charge sense resistor of 50mΩ.
To get a discharge short circuit condition requires 80A. To get a
discharge overcurrent condition requires a load of 40A. To get
a charge overcurrent condition requires 2A. Changing both
resistors to 0.5Ω provides a mechanism for easily testing the
current thresholds.
• To test the board in an application most likely requires that
battery cells be used and there is a large load available. While
the board was not extensively tested for these high load
currents, the traces are short and wide enough to (theoretically)
handle an overcurrent condition up to the 40A threshold.
Cell Balance Testing
• Testing the cell balance operation requires the use of Li-ion cells
or individual power supplies for each cell, or it requires modifying
the daughter board to use 1k cell balancing resistors instead of
the 200Ω or 39Ω resistors on the standard boards. With 6 cells
and VBAT = 20V, a string of 100 voltage divider resistors, and
39 cell balancing resistors, turning on one cell balance output
drops the voltage on that cell to about 1V. At this voltage, the
microcontroller puts the ISL94208 to sleep.
• As a quick test of the cell balance circuits, use the GUI to turn
on or off any combination of cell balance FETs using the
CB6:CB1 check boxes in the GUI Cell Balance frame.
• To test the software auto balance operation, start the cell
balance test by first observing if the cell with the maximum
cell voltage exceeds the cell with the minimum voltage by
more than 30mV. If so, note the cell number of the maximum
voltage cell.
• Next, on the GUI, select the Cell Balance “Max #” to be “1”. This
limits the balancing to only one cell (The one with the
maximum voltage).
• Monitor the cell balance LEDs on the board or the GUI to track
the cell balance operation. On the GUI, use the CB refresh
button (or start auto update) to update the indicators to show
which cell is being balanced, it should be the maximum
voltage cell. The board is set that the microcontroller balances
for 2s, then turn off balancing for 2 second, then balance
again. The maximum voltage cell is very close to the next
highest voltage cell, or if there are many cells within a narrow
voltage range, then any of these cells could be balanced, due
to the accuracy of the microcontroller A/D converter.
• For an application on, the balancing times may be too short. To
set the balance timers for a different configuration, go to the
“Pack Tab” in the GUI and change the cell balance on/off
times. Setting 1s on and 1s off is the minimum setting for cell
balancing, but 2s on, 2s off is the recommended minimum,
only because an autoscan of 1s can cause confusion due to
the asynchronous nature of cell balance and autoscan.
• Next, select the Cell Balance “Max #” to be “2”. This limits the
balancing to two cells (the highest two voltage cells). Again
refresh the CB screen periodically to see the operation of the
cell balance code.
• Open the pack tab in the GUI and change some of the settings
for overvoltage, undervoltage, or cell balance and re-test.
Remember to click on “Write” to send the new parameters to
the microcontroller.
Sleep/Wake Testing
The ISL94208 board can be put to sleep VIA commands from the
PC listed as follow:
There are three ways to put the ISL94208 into the sleep mode:
1. The easy way is to use the “Sleep” button below the register
access frame of the GUI.
2. You can also use the GUI register access window to write an
80H to the ISL94208 register 4.
3. Lowering the voltage on any cell below 2.3V for 1 second,
(default microcontroller software settings) causes the
microcontroller to put the ISL94208 to sleep. In case, the
operation turns off the ISL94208 RGO output and LED.
To wake up the ISL94208 requires that the ISL94208 WKUP pin go
below its wake up threshold. This can happen when a charger
connects to the pack charge terminals or when a load is connected
to the load terminals.
• The charger connection works, because it pulls the charger
negative terminal to about the ISL94208 VSS voltage, the same
as would an unloaded charger.
• The load connection works, because the load terminal is pulled
high (in sleep mode, the power FETs are off, so the connection
from the ISL94208 VSS pin to the Pack- pin is open.)
• Circuitry on the board inverts this signal to pull the ISL94208
WKUP pin low to wake the device.
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Application Note 1857
10kΩ
200kΩ
4.99kΩ
100kΩ
ISL94208
D1
2N7002
WKP0_L
WKUP
WKP0_C
In the Configure Tab of the GUI, the WKPOL pin can be set to
wake on a rising edge by checking the “WKUP Pin Active High”
box. This sets the ISL94208 WKPOL bit to 1. When this option is
selected, the ISL94208 wakens by a simulated microcontroller
command using the WKP1 switch.
VBACK
240kΩ
There are three wake up push buttons. In the default setting, the
ISL94208 WKPOL bit is 0. This forces a wake up when the WKUP
pin goes low. The ISL94208EVZ board has one push button that
pulls WKUP low, simulating the connection of a load (WKP0_L)
and one that pulls WKUP low simulating the connection of a
charger (WKP0_C). Pressing either button wakes the device.
VBAT
15V
The ISL94208 can be waken with real loads or chargers or by
using the push buttons as shown in Figure 7.
V
CFET DFET VSS
• When the ISL94208 wakes up it turns on the RGO output. This
turns on the RGO LED.
0.47µF/35V
DSC-
CHRG-
NOTES:
1. When the FETs are off, the WKP0_C button pulls the DSC- pin high,
as would connection to a load.
2. The WKP0_C button brings the WKUP input to near VSS, as would
connection to a load when the FETs are off. D1 prevents WKUP from
going negative if the charger is at a much higher voltage than the cells.
FIGURE 1. EXTERNAL WAKE UP CIRCUIT; WKPOL = 0
PACK+
49.9kΩ
270kΩ
WKP1
Polarity 0 - SIMULATED CHARGER CONNECT
Polarity 1- SIMULATED μC WAKE Up
Polarity 0- SIMULATED LOAD CONNECT
FIGURE 7. ISL94208EVZ WAKE UP BUTTONS
49.9kΩ
49.9kΩ
WKUP
ISL94208
V
200kΩ
µC
CFET DFET VSS
TUN ON, THEN OFF TO WAKE
(>60ms HIGH TIME)
DSC-
CHRG-
NOTES:
3. The components in blue wake the pack under control of the
microcontroller, however these are not included on the board.
4. The WKP1 switch simulates a wake up by the microcontroller.
FIGURE 1. EXTERNAL WAKE UP CIRCUIT; WKPOL = 1
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Application Note 1857
Additional Testing
Pack Voltage Monitoring
Further tests on the board will likely follow the lines of battery
pack testing, which can become quite involved and be very
specific to the application. Before setting up the tests, see the
“GUI user Guide” for information on using the interface and see
the “Microcode Reference Guide” for information about how the
software works.
The ISL94208EVZ has a circuit that is activated by the
microcontroller to monitor the pack voltage directly. The input
to the microcontroller is the pack voltage divided by 16 as
shown in Figure 9.
Other Board Features/Options
PACK+
100k
Current Direction Detection
The ISL94208EVZ board has a circuit to detect a charge or
discharge current (see Figure 8). This circuit is designed to detect
a small current flowing into or out of the pack.
There are two main uses for the current direction detection
circuit. The first is in power control. If the microcontroller does
not see any current for a long period of time, it can put the pack
hardware to sleep to extend battery life. Second, the cell balance
routine is usually conducted only during a charge condition. To do
this requires information that charge current is flowing.
The current direction detectors are comparators only, when the
current is high enough, the indicators go high. For charge current,
the threshold is about 100mA, for discharge the threshold is
about 800mA. These thresholds can be changed by replacing a
resistor, but making the thresholds much lower may cause
problems due to the op amp input offset. To change the
discharge current detection threshold, change the value of R46
as shown in Figure 8 (a lower value lowers the current threshold).
To change the charge current detection threshold, change the
value of R40 (a lower value lowers the current threshold).
1.21M
365k
82k
PACKV
16
TO μC
A/D INPUT
GND
TO μC
OUTPUT
49.9k
GND
FIGURE 9. DIRECT MONITOR OF THE PACK VOLTAGE
The purpose of this circuit is to get an alternate reading of the
pack voltage. Without this circuit, the pack voltage is determined
by adding the individual cell voltages. Having a separate reading
provides a “sanity check” that there are no gross cell
measurement errors.
PACK VOLTAGE MONITORING CIRCUIT
RGO
1M
1M
ISL28214
1 of 2
1k
1k R40
1M
CHARGE
INDICATOR
TO μC
FMMT619
GND
BSS84DW
CHARGE
0.05
0.005
DISCHARGE
RGO
0.005
ISL28214 2 of 2
PACK VOLTAGE ENABLE(PIN 6)
1.8M
1k
DISCHARGE
INDICATOR
TO μC
R46
PACK VOLTAGE μC INPUT (PIN 12)
FIGURE 10. ISL94208EVZ PACK VOLTAGE MONITORING
CONNECTIONS
FIGURE 8. USING OP AMP AND FETS TO DETECT CHARGE AND
DISCHARGE CURRENT
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Application Note 1857
FET Drive Voltages
Cell Balance Daughter Boards
In the ISL94208EVZ board, a separate regulator provides the
VFET1 and VFET2 reference voltages for the FET drive as shown
in Figure 11.
The ISL94208EVZ kit is provided with two daughter boards. The
main board can be used without either board, but there will be no
balancing. With no daughter boards, each VCELL input from the
battery pack has a 1k series resistor and a 22nF filter resistor to
ground.
There are three main reasons for doing this:
1. In a simple configuration where VCFET2 connects to VCELL3
and VFET1 connects to VCELL2, the FET reference current is
drawn primarily from CELL3 of the pack. Depending on the
FET drive current, this can unbalance the pack by having
different load characteristics across the cells. Using a
regulator supplies current from the top of the battery stack,
better maintaining balance.
2. When the voltage differential between VFET2 and VFET1
drops below approximately 2.8V, the FET drive has difficulty
providing enough current to fully drive the FETs. This gets
worse over-temperature. If the cell voltages drop below 2.3V
each, then a direct connection of the VFET pins to the CELL
pins can result in the FETs turning off (or not turning on.) Using
the regulator, it is possible to maintain the FET drive current
to cell voltages below 1.5V (6-cell pack).
3. By having the FET currents coming from the regulator it is
possible to better maintain measurement accuracy, since
there is no extra current flowing on an individual cell input.
The 100k resistor on the 4.3V regulator does not allow enough
current for the zener diode to regulate very well. Ideally, there
would be a 3V zener and a 5.6k resistor (1mA zener current).
However, this current significantly increases the pack current. By
using a higher voltage zener and a larger resistor, a similar result
is achieved with lower current. The actual differential voltage is
not too significant. As long as the VFET pin limits are maintained,
the differential does not drop below 2.8V
The VFET regulator is one from Intersil. This is not necessary, but
the regulator should be one that can be disabled so current is
very low when the ISL94208 goes to sleep and turns off RGO.
DB1 DAUGHTER BOARD
The DB1 daughter board uses the internal balancing FETs on the
ISL94208. When it is installed, balancing is not practical with 1k
input series resistors, because the voltage drops would be to big.
This would cause voltage measurement inaccuracies and the µC
on the board will interpret this as either an open circuit condition
or an undervoltage cell and put the board to sleep. To get around
this, this daughter board places a 20Ω resistor in parallel with the
1k on the main board and increases the filter capacitor to 1µF.
The filter on the CB pins should have the same time constant as
the VCELL pins.
The DB1 daughter board uses 200Ω balancing resistors. This is
about the smallest resistor possible, without having trouble with
voltage monitoring. When cell balance turns on between VCELLn
and VCELLn-1, the voltage at VCELLn-1 increases by about 10%
because of the 200Ω and 20Ω voltage divider between the cells,
as shown in Figure 12. The DB1 daughter board has a balance
current of about 16mA.
20
1µF
200
VCELLn
CBn
0.1µF
20
VCELLn-1
1µF
VSS
ISL94208
VBAT
ISL80136
ADJ
EN
0.47µF
16V
RGO
8.6V
VFET2
300kΩ
50kΩ
4.3V
10µF
16V
RGO
VFET1
100kΩ
VSS
FIGURE 11. ISL94208 EXAMPLE ALTERNATIVE VFET POWER
SUPPLY
VCELL Input Schottky Diodes
The ISL94208EVZ schematic shows five Schottky diodes on the
inputs between VCELLn and CB(n+1). These were added to help
deal with input surge currents during hot plugging the board into
a battery pack. However, with input resistors larger than 100Ω,
these components are not needed.
8
FIGURE 12. ISL94208DB1EVZ VCELL AND CB CONNECTION
DB2 DAUGHTER BOARD
The DB2 daughter board uses external balancing FETs. These are
p-channel devices driven by the CB outputs. When this board is
installed, the main board filters are left as-is with a 1k series
resistor and 22nF capacitor to ground. The daughter board only
adds the extra components for balancing as shown in Figure 13.
Because the balance current does not pass through the input
resistors, the monitored voltage does not change much when
being balanced or not being balanced. However, there likely is
some change. The DB2 balance circuit has about 100mA of
balance current. Because of this, there will likely be some
change in the source voltage (either a power supply or real cells).
If the Li-Ion cell has 20mΩ internal resistance, then the 100mA
of balance current will drop the measured voltage by 2mV. There
will also be some error due to the current through 500k and two
1k resistors when the CB output turns on. This error is on the
order of 7mV.
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Application Note 1857
The DB2 board does not provide much heat sinking for the
balance resistors. However, if five of the six balance outputs are
on at the same time, there will be about 2W of power dissipated.
This can cause the board to get hot. It is recommended that only
a few cells be balanced at the same time, if the test extends over
a long duration.
ISOLATED I2C INTERFACE CONNECTION
(MOTHERBOARD)
1k
22nF
VCELLn
500k
1k
CBn
39
1k
VCELLn-1
22nF
VSS
FIGURE 13. ISL94208DB1EVZ VCELL AND CB CONNECTION
BKGD CONNECTION
FIGURE 14. ISL94208EVZ ISOLATED INTERFACE AND BKGD
CONNECTIONS
I2C Isolation
Related Documentation
In some test conditions ground connections can cause problems.
This is because the I2C ground, power supply, load, and perhaps
an oscilloscope may all connect to ground. This can cause
problems ranging from grounding both sides of the power FETs
(taking them out of the circuit) to creating ground loops or
unexpected voltage potentials that can damage components.
From Intersil
The ISL 94208EVZ (Rev B) board provides an option for the
addition of an isolation device on the I2C interface, the Analog
Device ADuM1250. This allows the PC to monitor a battery pack
that is connected to a load without the grounding problems that
can arise from direct connect. To use this option, the device and a
header needs to be installed on the board, then the DeVaSys board
needs to connect to the JP3 connector as shown in Figure 14.
• ISL94208DB1EVZ (rev B) daughter board schematics
The DeVaSys board will need to connect with a 5- pin-to-5-pin
point--to-point connector (pin 3 is not used, but the ADuM1250
uses the 3.3V supply provided by the DeVaSys board).
SCHEMATICS/BILL OF MATERIAL
• ISL94208EVZ (rev B) board schematics
• ISL94208EVZ (rev B) board Bill of Material (BOM)
• ISL94208DB1EVZ (rev B) daughter board BOM
• ISL94208DB2EVZ (rev B) daughter board schematics
• ISL94208DB2EVZ (rev B) daughter board BOM
• MCB_PS_Z (rev B) board schematics
• MCB_PS_Z (rev B) board BOM
DOCUMENTS
ISL94208 Microcode Reference Guide
Microcontroller Options
ISL94208 FN8306 Data Sheet.
The BKGD connection on the ISL94208 board (see Figure 14)
allows development of new or modified code for the NXP
(formerly Freescale) MC9S08QG8 microcontroller, which is
supplied on the board.
ISL94208 Application Note.
ISL94208 GUI User Guide
DeVaSys USB-I2C software installation.
From NXP (Formerly Freescale)
MC9S08QG8 microcontroller data sheet.
HCS08 Microcontrollers Family Reference Manual.
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Application Note 1857
Appendix 1
Installing The DeVaSys USB to I2C Board
Software
Select “Install from a list or specific location” and click “Next” a
screen like the one shown will come up:
Obtain the Devasys software along with the GUI code from the
Intersil website on the ISL94208 page. Copy and extract the files
from the “ISL94208 Eval Kit Software Release V2.10” zip file to
the PC at whatever location is desired.
Disconnect the DeVaSys board from the ISL94208 board.
Then, plug in the DeVaSys board into the USB port.
The following screen should pop up.
Browse for the “Software” directory in the “ISL94208 Eval Kit SW
and docs” folder then click “Next”.
This should install the software, eventually bringing up the
following screen:
Select “Yes, this time only” and click “Next”.
The following screen will come up:
Click “Finish” and you’re done.
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Appendix 2
battery or source voltage to drop some voltage through the
leads connecting the supply to the board.
Communication Troubleshooting
If the voltages changing during balance is a problem, then it
is necessary to modify the code to turn off balance before
taking a cell voltage reading, then turn it on again if
conditions are still normal for balancing.
The GUI Starts Up With All Items “Grayed
Out”.
1. Check that the I2C cable is connected properly.
2. Check that the board is powered and that the RGO voltage is
~3.3V.
3. If the RGO voltage is not powered to the right voltage, move to
the power supply troubleshooting section.
4. Make sure that the board drivers are installed correctly.
On the DeVaSys USB to I2C interface board, there should be
one red LED and one green LED lighted.
5. If the LEDs on the DeVaSys board are not on, make sure that
the DeVaSys board is disconnected from the ISL94208 board
when it is first plugged into the PC.
6. Use a scope to see that the I2C communication is correct at
the board. Monitor the SCL and the SDA lines while initiating
a read of the ISL94208 status register. Set the scope to single
trigger on the falling edge of SCL.
Power Supply Troubleshooting
The RGO Does Not Have The Correct Voltage.
1. Check that the voltage on each of the input terminals are
between 2.6V and 4.5V.
2. Check that there is no unexpected load on the RGO output.
ISL94208 Troubleshooting
The AO Voltages Are Reading Incorrectly At The AO Pin.
The Cell Voltages Are Not Updated Correctly During
Refresh.
1. In the refresh function there is a bug when less than 6 cells
are connected. The auto-polling function works correctly, but
for manual update of cells 3, 4, and 5, it is necessary to select
the connected cell, click refresh, then select the displayed cell
and click refresh. For example, in a 4-cell pack CELL1, CELL2,
CELL5, and CELL6 inputs are used. To refresh the CELL3
voltage on the display requires selecting CELL5, clicking
“Refresh”, and then selecting CELL3 and clicking “Refresh”
again.
After Writing A Configuration Value, And Doing A Refresh,
The Value Returns To The Previous Setting.
1. There is a bug in the configuration write routine. It is supposed
to set the Write enable bit prior to writing the new setting, but
it does not do this properly. To ensure a proper operation,
write “E0” to register 08H before changing the configuration
value. This sets all write enable bits prior to write operation.
2. Another way that seems to work is to click on the
Configuration Write button two times allowing enough time
between clicks for the command to complete.
Other Questions
Forward any ISL94208EVZ questions to the Intersil Application
Engineer at [email protected]
1. Check that all cell balance outputs are off.
2. Make sure that there is minimal series resistance between the
battery and the input pins of the ISL94208EVZ board and that
the input voltages are between 2.6V and 4.3V.
GUI Troubleshooting
The Voltages Are Reading Incorrectly On The GUI.
1. Check that the RGO output is 3.3V. The GUI and
microcontroller calculations assume the RGO voltage is 3.3V.
Any variation translates directly into errors in the GUI screen
value.
2. Power-down the board and stop the GUI. Power up the board
and restart the GUI. This should clear any communication
problems.
3. Turn off the cell balancing. When using the DB1 daughter
board (internal balancing FETs) turning on the cell balancing
causes current flows into the CBN pin and out the VCELL(n-1)
pin. The current flowing out the VCELL(n-1) pin causes a
voltage drop across the input resistor on one side of the cell
measurement, but not the other. This can cause a
measurement error of up to 200mV to 300mV. This change
happens external to the ISL94208. Using the DB2 daughter
board, the voltage changes less, because the FET is external
and there is no balance current through the input series
resistors, however, the balancing current can cause the
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Application Note 1857
FIGURE 15. ISL94208EVZ (REV B) SCHEMATIC (PAGE 1 of 4)
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Application Note 1857
FIGURE 1. ISL94208EVZ (REV B) SCHEMATIC (PAGE 2 of 4)
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Application Note 1857
FIGURE 16. ISL94208EVZ (REV B) SCHEMATIC (PAGE 3 of 4)
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Application Note 1857
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FIGURE 16. ISL94208EVZ (REV B) SCHEMATIC (PAGE 4 of 4)
Application Note 1857
TABLE 1. ISL94208 BILL OF MATERIALS (MAIN BOARD)
Part Number
ISL94208EVZREVBPCB
Qty
Units
1
ea
Reference Designator
DESCRIPTION
PWB-PCB, ISL94208EVZ, REVB, ROHS
GMK212BJ474KG-T
2
ea
C12, C17
CAP, SMD, 0805, 0.47µF, 35V, 10%, X5R, ROHS
H1044-00102-25V10-T
1
ea
C3
CAP, SMD, 0402, 1000pF, 25V, 10%, X7R, ROHS
H1044-00103-16V10-T
1
ea
C15
CAP, SMD, 0402, 1µF, 16V, 10%, X7R, ROHS
H1044-00104-16V10-T
1
ea
C18
CAP, SMD, 0402, 0.1µF, 16V, 10%, X7R, ROHS
H1045-00102-25V10-T
1
ea
C16
CAP, SMD, 0603, 1000PF, 25V, 10%, X7R, ROHS
H1045-00104-16V10-T
2
ea
C13, C14
CAP, SMD, 0603, 0.1µF, 16V, 10%, X7R, ROHS
H1045-00106-6R3V20-T
1
ea
C8
CAP, SMD, 0603, 10µF, 6.3V, 20%, X5R, ROHS
H1045-00223-50V10-T
7
ea
C1, C2, C6, C9, C10, C19, C20
CAP, SMD, 0603, 0.022µF, 50V, 10%, X7R, ROHS
H1045-DNP
0
ea
C25, C26
CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS
H1046-00106-16V8020-T
1
ea
C11, C30
CAP, SMD, 0805, 10µF, 16V, +80-20%, Y5V, ROHS
H1065-DNP
2
ea
C4, C5
CAP, SMD, 1206, DNP-PLACE HOLDER, ROHS
H1082-00105-50V10-T
1
ea
C7
CAP, SMD, 1210, 1µF, 50V, 10%, X7R, ROHS
1266
1
ea
B- (Located right of J10)
CONN-TERMINAL, TH, QUICK-FIT MALE TAB, 20.1x8.9, ROHS
22-28-8361-1X2
1
ea
JP2
CONN-HEADER, 1X2, BRK-AWAY 1X36, 2.54mm, R/A, ROHS
22-28-8361-1X4
1
ea
J29
CONN-HEADER, 1X4, BRK-AWAY 1X36, 2.54mm, R/A, ROHS
22-28-8361-1X7
1
ea
J8
CONN-HEADER, 1X7, BRK-AWAY 1X36, 2.54mm, R/A, ROHS
67996-272HLF-2X3
1
ea
JP1
CONN-HEADER, 2x3, BRKAWY 2X36, 2.54mm, VERTICAL, ROHS
929974-01-36-RK-1X7
1
ea
J7
CONN-SOCKET, TH, 1X7, BRKAWY 1X36, 2.54mm, INSULATED, ROHS
AZ23C3V3-7-F-T
1
ea
D5
DIODE-ZENER, DUAL, SMD, SOT23, 3.3V, 300mW, ROHS
BAT6203WE6327XT
4
ea
D2, D4, D13, D15
DIODE-SCHOTTKY, SMD, 2P, SOD323, 40V, 20mA, ROHS
MBR0540T1G-T
5
ea
D26-D30
DIODE-SHOTTKEY RECTIFIER, SMD, SOD-123, 40V, 0.5A, ROHS
MM3Z4V3T1G-T
1
ea
D1
DIODE-ZENER, SMD, SOD-323, 4.3V, 200mW, ROHS
MMSZ4702T1G-T
1
ea
D25
DIODE-ZENER, SMD, 2P, SOD-123, 15V, 500mW, ROHS
MMSZ4705T1G-T
2
ea
D16, D23
DIODE-ZENER, SMD, 2P, SOD-123, 18V, 500mW, ROHS
MMSZ4713T1G-T
1
ea
D3
DIODE-ZENER, SMD, 2P, SOD-123, 30V, 500mW, ROHS
LNJ326W83RA-T
1
ea
D12
LED, SMD, 0603, GREEN, 2.05V, 17mcd, 10mA, ROHS
ISL28214FUZ
1
ea
U2
IC-DUAL OP AMP, RRIO, 8P, MSOP, ROHS
ISL80136IBEAJZ
1
ea
U6
IC-40V LDO ADJ. LINEAR REGULATOR, 8P, EPSOIC, ROHS
ISL94208IRZ
1
ea
U1
IC-MULTI-CELL LI-ION BATTERY, 32P, QFN, 5X5, ROHS
MC9S08QG8CFFE
1
ea
U3
IC-MCU, FLASH, 8Kx8, 10MHz, 16P, QFN, ROHS
2N7002-7-F-T
1
ea
Q3
TRANSISTOR, N-CHANNEL, 3LD, SOT-23, 60V, 115mA, ROHS
BC817-40W-7-T
1
ea
Q13
TRANSISTOR-NPN, SMD, 3P, SOT-323, 45V, 500mA, ROHS
BSS8402DW-7-F-T
1
ea
Q5
TRANSIST-MOS, P-CHANNEL/N-CHANNEL, 6P, SOT-363, 200mW, ROHS
BSS84DW-7-F-T
1
ea
Q4
TRANSIST, DUAL P-CHANNEL, 6P, SOT-363, -50V, -130mA, ROHS
FMMT619TA-T
1
ea
Q1
TRANSISTOR, NPN, SOT23, 50V, 2A, ROHS
IRF1404SPBF
2
ea
Q2, Q12
TRANSIST-MOS, N-CHANNEL, TH, D2-PAK, 40V, 162A, ROHS
IRF7469PBF
2
ea
Q14, Q15
TRANSISTOR-MOS, SMPS, 8P, SOIC, 40V, 9A, ROHS
CSNL20.0051%R-T
2
ea
R52, R53
RES-CURR SENSE, SMD, 2512, 0.005ohm, 2W, 1%, MF, ROHS
CSRN20.051%I-T
1
ea
R50
RES-CURR SENSE, SMD, 2512, 0.05ohm, 2W, 1%, TF, ROHS
H2510-01001-1/16W1-T
3
ea
R34, R40, R46
RES, SMD, 0402, 1k, 1/16W, 1%, TF, ROHS
H2510-01002-1/16W1-T
3
ea
R93
RES, SMD, 0402, 10k, 1/16W, 1%, TF, ROHS
H2510-01003-1/16W1-T
3
ea
R2, R36, R66
RES, SMD, 0402, 100k, 1/16W, 1%, TF, ROHS
H2510-01004-1/16W1-T
5
ea
R26, R27, R42, R43, R64
RES, SMD, 0402, 1MEG, 1/16W, 1%, TF, ROHS
H2510-01005-1/16W1-T
1
ea
R48
RES, SMD, 0402, 10M, 1/16W, 1%, TF, ROHS
H2510-01204-1/16W1-T
1
ea
R49
RES, SMD, 0402, 1.2MEG, 1/16W, 1%, TF, ROHS
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TABLE 1. ISL94208 BILL OF MATERIALS (MAIN BOARD) (Continued)
H2510-01804-1/16W1-T
1
ea
R75
RES, SMD, 0402, 1.8M, 1/16W, 1%, TF, ROHS
H2510-02003-1/16W1-T
3
ea
R94
RES, SMD, 0402, 200k, 1/16W, 1%, TF, ROHS
H2510-02703-1/16W1-T
3
ea
R92
RES, SMD, 0402, 270k, 1/16W, 1%, TF, ROHS
H2510-03003-1/16W1-T
3
ea
R84
RES, SMD, 0402, 300k, 1/16W, 1%, TF, ROHS
H2510-03653-1/16W1-T
1
ea
R6
RES, SMD, 0402, 365k, 1/16W, 1%, TF, ROHS
H2510-04642-1/16W1-T
1
ea
R38
RES, SMD, 0402, 46.4k, 1/16W, 1%, TF, ROHS
H2510-04701-1/16W1-T
4
ea
R3, R4, R81, R82
RES, SMD, 0402, 4.7k, 1/16W, 1%, TF, ROHS
H2510-04991-1/16W1-T
2
ea
R47, R95
RES, SMD, 0402, 4.99k, 1/16W, 1%, TF, ROHS
H2510-04992-1/16W1-T
2
ea
R54, R91
RES, SMD, 0402, 49.9k, 1/16W, 1%, TF, ROHS
H2510-049R9-1/16W1-T
1
ea
R67
RES, SMD, 0402, 49.9Ω, 1/16W, 1%, TF, ROHS
H2510-08202-1/16W1-T
1
ea
R51
RES, SMD, 0402, 82k, 1/16W, 1%, TF, ROHS
H2511-01000-1/10W1-T
4
ea
R28, R29, R33, R35
RES, SMD, 0603, 100Ω, 1/10W, 1%, TF, ROHS
H2511-01001-1/10W1-T
0
ea
DNP - R8, R9
RES, SMD, 0603, 1k, 1/10W, 1%, TF, ROHS
H2511-01001-1/10W1-T
10
ea
R7, R10, R11, R13, R15, R17,
R19, R21, R41, R62.
RES, SMD, 0603, 1k, 1/10W, 1%, TF, ROHS
H2511-01002-1/10W1-T
2
ea
R45, R103
RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS
H2511-01004-1/10W1-T
1
ea
R65
RES, SMD, 0603, 1M, 1/10W, 1%, TF, ROHS
H2511-02403-1/10W1-T
1
ea
R5
RES, SMD, 0603, 240k, 1/10W, 1%, TF, ROHS
H2511-02493-1/10W1-T
1
ea
R39
RES, SMD, 0603, 249k, 1/10W, 1%, TF, ROHS
H2511-04990-1/10W1-T
1
ea
R37
RES, SMD, 0603, 499Ω, 1/10W, 1%, TF, ROHS
H2511-04991-1/10W1-T
1
ea
R23
RES, SMD, 0603, 4.99k, 1/10W, 1%, TF, ROHS
H2511-05110-1/10W1-T
1
ea
R1
RES, SMD, 0603, 511Ω, 1/10W, 1%, TF, ROHS
H2511-DNP
0
ea
R83
RES, SMD, 0603, DNP-PLACE HOLDER, ROHS
H2512-00270-1/8W1-T
1
ea
R63
RES, SMD, 0805, 27Ω, 1/8W, 1%, TF, ROHS
FSMSMTR-T
3
ea
S1, S2, S3
SWITCH-TACTILE, SMD, 6X3.5, 12V, 0.05A, SPST-NO, ROHS
DNP
0
ea
C28
DO NOT POPULATE OR PURCHASE
DNP
0
ea
J10, J42
DO NOT POPULATE OR PURCHASE
DNP
0
ea
JP3 (22-23-2051)
DO NOT POPULATE OR PURCHASE
DNP
0
ea
R76
DO NOT POPULATE OR PURCHASE
DNP
0
ea
U4 (ADUM1250ARZ)
DO NOT POPULATE OR PURCHASE
DNP
0
ea
a) CSns, DSns, CFET, DFET,
TMPI, RGO, RGC, AO,
DO NOT POPULATE OR PURCHASE
DNP
0
ea
b) SCL, SDA, PSCL, PSDA, VMon, DO NOT POPULATE OR PURCHASE
WKUP
DNP
0
ea
c) Dgate, TEMP3V, Pack-DSC,
Pack-CHG, A2DIN
DNP
0
ea
d) µCP1, µCP2, ENI, ENPV, CHI, DO NOT POPULATE OR PURCHASE
DCI, PV
17
DO NOT POPULATE OR PURCHASE
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TABLE 2. ISL94208 BILL OF MATERIALS (DAUGHTER BOARD 1)
PART NUMBER
QTY UNITS
REFERENCE DESIGNATOR
DESCRIPTION
ISL94208DB1EVZREVBPCB
1
ea
PWB-PCB, ISL94208DB1EVZ, REVB, ROHS
H1045-00104-50V10-T
6
ea
C21-C24, C27, C29
CAP, SMD, 0603, 0.1µF, 50V, 10%, X7R, ROHS
H1045-00105-50V10-T
6
ea
C31-C37
CAP, SMD, 0603, 1µF, 50V, 10%, X7R, ROHS
929834-01-36-RK-1X13
1
ea
J17
CONN-HEADER, TH, 1x13, BRKAWY 1x36, 2.54mm, ROHS
929834-01-36-RK-1X7
1
ea
J9
CONN-HEADER, TH, 1x7, BRKAWY 1x36, 2.54mm, ROHS
LNJ826W83RA-T
6
ea
D6-D11
LED, SMD, 0603, ORANGE, 19mcd, 5mA, 1.9V, 620nm, ROHS
H2510-07500-1/16W1-T
6
ea
R56-R61
RES, SMD, 0402, 750Ω, 1/16W, 1%, TF, ROHS
H2515-02000-1W5-T
6
ea
R85-R90
RES, SMD, 2512, 200Ω, 1W, 5%, TF, ROHS
H2511-00200-1/10W1-T
4
ea
R96-R102
RES, SMD, 0603, 20Ω, 1/10W, 1%, TF, ROHS
TABLE 3. ISL94208 BILL OF MATERIALS (DAUGHTER BOARD 2)
PART NUMBER
QTY UNITS
REFERENCE DESIGNATOR
DESCRIPTION
ISL94208DB2EVZREVBPCB
1
ea
PWB-PCB, ISL94208DB2EVZ, REVB, ROHS
929834-01-36-RK-1X13
1
ea
J24
CONN-HEADER, TH, 1x13, BRKAWY 1x36, 2.54mm, ROHS
929834-01-36-RK-1X7
1
ea
J11
CONN-HEADER, TH, 1x7, BRKAWY 1x36, 2.54mm, ROHS
LNJ826W83RA-T
6
ea
D17-D22
LED, SMD, 0603, ORANGE, 19mcd, 5mA, 1.9V, 620nm, ROHS
MMBT3906K-T
6
ea
Q6-Q11
TRANSISTOR, PNP, 3P, SOT-23, -40V, -200mA, ROHS
H2510-01001-1/16W1-T
6
ea
R12, R14, R16, R18, R20, R22
RES, SMD, 0402, 1k, 1/16W, 1%, TF, ROHS
H2510-04993-1/16W1-T
6
ea
R73, R74, R77-R80
RES, SMD, 0402, 499k, 1/16W, 1%, TF, ROHS
H2510-07500-1/16W1-T
6
ea
R24, R25, R30, R31, R32, R44
RES, SMD, 0402, 750Ω, 1/16W, 1%, TF, ROHS
H2515-00390-1W1-T
6
ea
R55, R68-R72
RES, SMD, 2512, 39Ω, 1W, 1%, TF, ROHS
Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is
cautioned to verify that the Application Note or Technical Brief is current before proceeding.
For information regarding Intersil Corporation and its products, see www.intersil.com
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