5
AN1562.0
April 1, 2010
If the Visa resource name is blank, it indicates a
problem with the USB communication.
Clicking on the “RESET INTERFACE” button may
correct the problem. If not, try closing the software,
remove power and USB connections from the
evaluation board, then reconnect and restart.
Note the register contents are updated ONLY when the
Read All button is clicked.
The Write Charge Current Button sends only the
charge current to the ISL9519. Other registers are
unchanged.
The small white window next to “Charge Current”
accepts inputs in Amps, and converts them the
hexadecimal (hex) value to be written to the ISL9519
in the grey window. The hex value depends on the
value entered in Sense R. The value in the white
window will be forced to the nearest valid number that
can be produced by the DAC in the ISL9519. That is,
after entering 4 and hitting the enter key, the display
will change to 3.968. After entering 4.1 and hitting the
enter key, the display will change to 4.096. The value
can be incremented and decremented with the
up/down arrows at the left of the window.
The Sense R inputs are used to calculate the
hexadecimal (hex) values and the SMBus sequences
for the Charge Current limit and Input Current limit
entered in the white boxes. The evaluation board is
built with 10m
Ω
sense resistors. If you change them to
another value, enter the new value to get correct
calculations.
After entering a number in the white box, hitting the
enter key or clicking on another area will enter the
value and the resulting hex value and the SMBus
sequence will be calculated and displayed.
.
S = the Start condition, A = the Acknowledge, P = the
Stop condition.
Note: The LO byte is sent first. The HI byte is sent
second.
When writing 0x41A0, 0xA0 is written first and 0x41 is
sent second.
Important Note: The SMBus commands are NOT
sent until one of the WRITE buttons is clicked
(i.e. Write All or Write Charge Current)
Important Note: Max System Voltage Commands
that a much higher than the voltage for the
number of cells selected by the CELL pin are
ignored (not acknowledged). Please refer to the
Max System Voltage section of the datasheet for
details.
The Write MaxSystem Voltage button writes only the
MaxSystem Voltage register. Other registers are
unchanged.
The small white window accepts Max System Voltage
(in Volts) and calculates the hexadecimal value and the
SMBus sequence to write to the ISL9519. The SMBus
command is sent when the Write MaxSystem Voltage
or Write All button is clicked. See Figure 8.
The Write Input Current button writes only the Charge
Current register. Other registers are unchanged. The
small white window accepts Input Current Limit in
Amps and calculates the hex value and the SMBus
sequence to be written to the ISL9519. The Sense R
input Is used to calculate the hex value and the SMBus
sequence. The SMBus command is sent when the Write
Input Current or Write All button is clicked. See
Figure 9.
The ISL9519 will shut down unless it receives
MaxSystem Voltage or Charge Current commands
every 175s. This is a safety feature that prevents
overcharging batteries if bus master has stopped
functioning. A toggle switch can be set to tell the
software to write all commands every 60 seconds.
Application Note 1562
