ISL9208EVAL2Z Intersil, ISL9208EVAL2Z Datasheet - Page 5

• Manufacturer Part Number: ISL9208EVAL2Z
• Description: EVAL BOARD 2 FOR ISL9208
• Manufacturer: Intersil

Specifications of ISL9208EVAL2Z

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

• Next, select “CB Max #” to be “1”. This limits the balancing
• Monitor the call balance LEDs on the board or the GUI to
• Next, select “CB Max #” to be “2”. This limits the balancing
• Open the pack tab in the GUI and change some of the
Sleep/Wake Testing
The ISL9208 board can be put to sleep via commands from
the PC or by lowering the voltage on any cell below 2.5V
(default software setting). This sequence is described in the
following paragraphs.
To put the ISL9208 into the sleep mode, use the Register
Access window to write an 80H to the ISL9208 register 4.
This turns off the ISL9208 RGO output and LED. Or, the
ISL9208 can be put to sleep by the microcontroller
automatically when it detects that the voltage on any cell is
less than 2.5V.
To wake-up the ISL9208 requires that the ISL9208 WKUP
pin go below its walk-up threshold.This can happen when a
charger connects to the pack charge terminals or when a
load is connected to the load terminals. This can be done
with real loads or chargers or by using a resistor, as shown
in Figure 6.
1.
minimum voltage by more than 30mV. If so, note the cell
number of the maximum voltage cell.
to only one cell - the one with the maximum voltage.
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. Be patient, because the
microcontroller will balance for 10s, then turn off balancing
for 2s
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 limited accuracy
of the microcontroller A/D converter.
to two cells - the highest two voltage cells. Again refresh
the CB screen periodically to see the operation of the cell
balance code.
settings for overvoltage, undervoltage, or cell balance and
re-test. Remember to click on “Write” to send the new
parameters to the microcontroller.
If this is too long to wait, 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.
1
, then balance again. Also, if the maximum voltage
5
Application Note 1444
• The charger connection works because it pulls the charger
• The load connection works, because the load terminal is
• When the WKUP pin is pulled low, the ISL9208 wakes up
Additional Testing
Further tests on the board will likely follow the lines of battery
pack testing, so it can become quite involved and be very
specific to the application. Therefore, before setting up the
tests, see the “GUI user Manual” for information on using the
interface and see the “Microcode Reference Guide” for
information about how the software works.
Other Board Features/Options
Current Direction Detection
The ISL9208EVAL2Z (Rev A) board has a circuit to detect a
charge or discharge condition (see Figure 7). It is designed
to detect a small current flowing into or out of the pack. The
software revision 1.5 does not yet support this hardware, but
the signals can be monitored with a meter or a scope to
determine their performance.
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, so
when the current is high enough, the indicators go high. For
CONNECT TO SIMULATE
CHARGER WAKE-UP
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negative terminal to about the ISL9208 VSS voltage, the
same as would an unloaded charger.
pulled high (in sleep mode, the power FETs are off, so the
connection from the ISL9208 VSS pin to the Pack- pin is
open). Circuitry on the board inverts this signal to pull the
ISL9208 WKUP pin low to wake the device.
and turns on the RGO output. This turns on the RGO LED.
FIGURE 6. ISL9208EVAL2Z CURRENT DETECTION
CONNECTIONS
CONNECT TO SIMULATE
LOAD WAKE-UP
December 15, 2008
AN1444.0
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