ISL94200IRZ Intersil, ISL94200IRZ Datasheet - Page 20

• Manufacturer Part Number: ISL94200IRZ
• Description: IC MULTI LI-ION OC PROT 24-QFN
• Manufacturer: Intersil

Specifications of ISL94200IRZ

• Function: Over/Under Voltage Protection
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 5 V ~ 10 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Turning off the FETs in the event of an over-temperature
condition prevents continued discharge or charge of the cells
when they are over heated.
In the event of an automatic over-temperature condition the
FETs are held off until the temperature drops back below the
temperature recovery threshold. During this temperature
shutdown period, the microcontroller can monitor the internal
temperature through the analog output pin (AO), but any
writes to the CFET or DFET bits are ignored
The automatic response to an internal over-temperature is
prevented by setting the DISITSD bit to “1”. The automatic
response to an external over-temperature is prevented by
setting the DISXTSD bit to “1”. In either case, it is important
for the microcontroller to monitor the internal and external
temperature to protect the pack and the electronics in an
over-temperature condition.
Analog Multiplexer Selection
The ISL94200 devices can be used to externally monitor
individual battery cell voltages and temperatures. Each
quantity can be monitored at the analog output pin (AO). The
desired voltage is selected using the I
AO3:AO0 bits. See Figure 6.
VOLTAGE MONITORING
Since the voltage on each of the Li-ion Cells are normally
higher than the regulated supply voltage, and since the
voltages on the upper cells is much higher than is tolerated
by a microcontroller, it is necessary to both level shift and
divide the voltage before it can be monitored by the
microcontroller or an external A/D converter. To get into the
voltage range required by the external circuits, the voltage
level shifter divides the cell voltage by 2 and references it to
VSS. Therefore, a Li-ion cell with a voltage of 4.2V becomes
a voltage of 2.1V on the AO pin.
TEMPERATURE MONITORING
The voltage representing the external temperature applied at
the TEMPI terminal is directed to the AO terminal through a
MUX, as selected by the AO control bits (see Figures 5
and 6). The external temperature voltage is not divided by 2
as are the cell voltages. Instead it is a direct reflection of the
voltage at the TEMPI pin.
A similar operation occurs when monitoring the internal
temperature through the AO output, except there is no
external “calibration” of the voltage associated with the
internal temperature. For the internal temperature
monitoring, the voltage at the output is linear with respect to
temperature. See “Operating Specifications” for information
about the output voltage at +25°C and the output slope
relative to temperature on page 6.
20
2
C interface and the
ISL94200
I
AO
SCL
SDA
2
AO
C
FIGURE 5. EXTERNAL TEMPERATURE MONITORING
FIGURE 6. ANALOG OUTPUT MONITORING DIAGRAM
TEMP FAIL
INDICATOR
XOT
DECODE
MUX
AO3:AO0
I
2
C
2
AND CONTROL
EXT TEMP
AO3:AO0
DECODE
ATMPOFF
TMP3ON
REGS
MUX
MUX
I
2
OSC
C
VSS (ON)
DELAY
EXTERNAL
MONITOR
1ms
TEMP
4ms
508ms
EXT TEMP.
LEVEL
LEVEL
LEVEL
LEVEL
SHIFT
SHIFT
SHIFT
SHIFT
TEMP
INT
TEMPI
VSS
VSS
RGO
TEMP3V
VC7/VCC
VCELL6
VCELL2
VCELL1
TEMPI
R
July 3, 2008
X
FN6718.0
TO
µC