ISL9208 Intersil Corporation, ISL9208 Datasheet - Page 3

• Manufacturer Part Number: ISL9208
• Description: Multi-Cell Li-ion Battery Pack OCP/Analog Front End
• Manufacturer: Intersil Corporation

Pin Names
VC7/VCC Battery cell 7 voltage input/VCC supply. This pin is used to monitor the voltage of this battery cell externally at pin
SYMBOL
DSENSE Discharge current sense monitor. This input monitors the discharge current by monitoring a voltage. It can monitor
CSENSE Charge current sense monitor. This input monitors the charge current by monitoring a voltage. It can monitor the
VCELLN Battery cell N voltage input. This pin is used to monitor the voltage of this battery cell externally at pin AO. VCELLN
TEMP3V Temperature monitor output control. This pin outputs a voltage to be used in a divider that consists of a fixed resistor
DSREF
VMON
TEMPI
DFET
CFET
CBN
VSS
AO
AO. This pin also provides the operating voltage for the IC circuitry.
connects to the positive terminal of CELLN and the negative terminal of CELLN + 1.
Cell balancing FET control output N. This internal FET diverts a fraction of the current around a cell while the cell is
being charged or adds to the current pulled from a cell during discharge in order to perform a cell voltage balancing
operation. This function is generally used to reduce the voltage on an individual cell relative to other cells in the pack.
The cell balancing FETs are turned on or off by an external controller.
Ground. This pin connects to the most negative terminal in the battery string.
Discharge current sense reference. This input provides a separate reference point for the charge and discharge
current monitoring circuits. WIth a separate reference connection, it is possible to minimize errors that result from
voltage drops on the ground lead when the load is drawing large currents. If a separate reference is not necessary,
connect this pin to VSS.
the voltage across a sense resistor, or the voltage across the DFET, or by using a FET with a current sense pin. The
voltage on this pin is measured with reference to DSREF.
voltage across a sense resistor, or the voltage across the CFET, or by using a FET with a current sense pin. The voltage
on this pin is measured with reference to VSS.
Discharge FET control. The ISL9208 controls the gate of a discharge FET through this pin. The power FET is a
N-Channel device. The FET is turned on only by the microcontroller. The FET can be turned off by the microcontroller,
but the ISL9208 also turns off the FET in the event of an overcurrent or short circuit condition. If the microcontroller
detects an undervoltage condition on any of the battery cells, it can turn off the discharge FET by controlling this output
with a control bit.
Charge FET control. The ISL9208 controls the gate of a charge FET through this pin. The power FET is a N-Channel
device. The FET is turned on only by the microcontroller. The FET can be turned off by the microcontroller, but the
ISL9208 also turns off the FET in the event of an overcurrent condition. If the microcontroller detects an overvoltage
condition on any of the battery cells, it can turn off the FET by controlling this output with a control bit.
Discharge load monitoring. In the event of an overcurrent or short circuit condition, the microcontroller can enable an
internal resistor that connects between the VMON pin and VSS. When the FETs open because of an overcurrent or
short circuit condition and the load remains, the voltage at VMON will be near the VCC voltage. When the load is
released, the voltage at VMON drops below a threshold indicating that the overcurrent or short circuit condition is
resolved. At this point, the LDFAIL flag is cleared and operation can resume.
Analog multiplexer output. The analog output pin is used by an external microcontroller to monitor the cell voltages
and temperature sensor voltages. The microcontroller selects the specific voltage being applied to the output by writing
to a control register.
and a thermistor. The thermistor is located in close proximity to the cells. The TEMP3V output is connected internally
to the RGO voltage through a PMOS switch only during a measurement of the temperature, otherwise the TEMP3V
output is off. The TEMP3V output can be turned on continuously with a special control bit.
Microcontroller wake up control. The TEMP3V pin is also turned on when any of the DSC, DOC, or COC bits are set.
This can be used to wake up a sleeping microcontroller to respond to overcurrent conditions with its own control
mechanism.
Temperature monitor input. This pin inputs the voltage across a thermistor to determine the temperature of the cells.
When this input drops below TEMP3V/13, an external over-temperature condition exists. The TEMPI voltage is also fed
to the AO output pin through an analog multiplexer so the temperature of the cells can be monitored by the
microcontroller.
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ISL9208
DESCRIPTION
February 16, 2007
FN6446.0