ISL9208 Intersil Corporation, ISL9208 Datasheet - Page 18

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

.
Device Description
Design Theory
Instructed by the microcontroller, the ISL9208 performs cell
voltage monitoring and cell balancing operations,
overcurrent and short circuit monitoring with automatic pack
shutdown using built-in selectable time delays, and
automatic turn off of the power FETs and cell balancing FETs
in an over-temperature condition. All automatic functions of
the ISL9208 can be turned off and the microcontroller can
manage the operations through software.
Battery Connection
The ISL9208 supports packs of 5 to 7 series connected
Li-ion cells. Connection guidelines for each cell combination
are shown in Figure 1.
BIT
7
6
5
4
3
2
1
0
FIGURE 1. BATTERY CONNECTION OPTIONS
Note: Multiple cells can be connected in parallel
VCELL7
CB7
VCELL6
CB6
VCELL5
CB5
VCELL4
CB4
VCELL3
CB3
VCELL2
CB2
VCELL1
CB1
VSS
7 CELLS
FSETEN
Enable discharge set writes
CHSETEN
Enable charge set writes
DISSETEN
Enable discharge set writes
UFLG3
User Flag 3
UFLG2
User Flag 3
RESERVED
RESERVED
RESERVED
FUNCTION
18
VCELL7
VCELL6
VCELL5
VCELL4
VCELL3
VCELL2
VCELL1
VSS
CB7
CB6
CB5
CB4
CB3
CB2
CB1
6 CELLS
When set to “1”, allows writes to the Feature Set register. When set to “0”, prevents writes to the Feature
Set register (Addr: 07H). Default on initial power up is “0”.
When set to “1”, allows writes to the Charge Set register. When set to “0”, prevents writes to the Feature
Set register (Addr: 06H). Default on initial power up is “0”.
When set to “1”, allows writes to the Discharge Set register (Addr: 05H). When set to “0”, prevents writes
to the Feature Set register. Default on initial power up is “0”.
General purpose flag usable by microcontroller software. This bit is battery backed up, even when RGO
turns off.
General purpose flag usable by microcontroller software. This bit is battery backed up, even when RGO
turns off.
Reserved for future expansion.
Reserved for future expansion.
Reserved for future expansion.
TABLE 10. WRITE ENABLE REGISTER (ADDR: 08H)
VCELL7
CB7
VCELL6
CB6
VCELL5
CB5
VCELL4
CB4
VCELL3
CB3
VCELL2
CB2
VCELL1
CB1
VSS
5 CELLS
ISL9208
System Power Up/Power Down
The ISL9208 powers up when the voltages on V
V
At this time, the ISL9208 wakes up and turns on the RGO
output.
RGO provides a regulated 3.3VDC ±10% voltage at pin
RGO. It does this by using a control voltage on the RGC pin
to drive an external NPN transistor (See Figure 2.) The
transistor should have a beta of at least 70 to provide ample
current to the device and external circuits and should have a
V
emitter of the NPN transistor is monitored and regulated to
3.3V volts by the control signal RGC. RGO also powers most
of the ISL9208 internal circuits. A 500Ω resistor is
recommended in the collector of the NPN transistor to
minimize initial current surge when the regulator turns on.
Once powered up, the device remains in a wake up state
until put to sleep by the microcontroller (typically when the
cells drop too low in voltage) or until the V
V
CELL2
CE
CELL3
of greater than 30V (preferably 50V). The voltage at the
DESCRIPTION
, V
, or VCC voltages drop below their POR threshold.
FIGURE 2. VOLTAGE REGULATOR CIRCUITS
CELL3
, and VCC all exceed their POR threshold.
VCC
VSS
RGC
RGO
500
CELL1
February 16, 2007
, V
CELL1
3.3V
GND
CELL2
FN6446.0
,
,