ISL6292-2CR5Z Intersil, ISL6292-2CR5Z Datasheet - Page 13

• Manufacturer Part Number: ISL6292-2CR5Z
• Description: IC CHARGER LI-ION POLYMER 16-QFN
• Manufacturer: Intersil

Specifications of ISL6292-2CR5Z

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Pol)
• Voltage - Supply: 4.3 V ~ 6.5 V
• Operating Temperature: -20°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-VQFN Exposed Pad, 16-HVQFN, 16-SQFN, 16-DHVQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

End-of-Charge (EOC) Current
The end-of-charge current I
charger starts to indicate the end of the charge with the
STATUS pin, as shown in Figure 19. The charger actually
does not terminate charging until the end of the TIMEOUT,
as described in “Total Charge Time” on page 12. The I
set in two ways, by connecting a resistor between the IMIN
pin and ground, or by connecting the IMIN pin to the V2P8
pin. When programming with the resistor, the I
Equation 6.
where R
and the ground. When connected to the V2P8 pin, the I
is set to 1/10 of I
GND. Under this exception, I
the 3x3 DFN package, the IMIN pin is bonded internally to
V2P8.
Charge Current Thermal Foldback
Over-heating is always a concern in a linear charger. The
maximum power dissipation usually occurs at the beginning
of a charge cycle when the battery voltage is at its minimum
but the charge current is at its maximum. The charge current
thermal foldback function in the ISL6292 frees users from
the over-heating concern.
Figure 20 shows the current signals at the summing node of
the current error amplifier CA in the Block Diagram shown on
page 9. I
Temperature Monitoring block. The I
charge current until the internal temperature reaches
approximately +100°C; then I
When I
current I
current, the charge current is 100,000 times that of the
sensed current and reduces at a rate of 100mA/°C. For a
charger with the constant charge current set at 1A, the
charge current is reduced to zero when the internal
temperature rises to +110°C. The actual charge current
settles between +100°C to +110°C.
Usually the charge current should not drop below I
of the thermal foldback. For some extreme cases (if that does
happen) the charger does not indicate end-of-charge unless
the battery voltage is already above the recharge threshold.
I
MIN
FIGURE 20. CURRENT SIGNALS AT THE AMPLIFIER CA INPUT
=
T
10000
SEN
IMIN
R
rises, the current control loop forces the sensed
is the reference and I
to reduce at the same rate. As a mirrored
is the resistor connected between the IMIN pin
⋅
----------------
R
V
REF
IMIN
REF
, except when the IREF pin is shorted to
=
----------------
R
0.8V
IMIN
MIN
MIN
13
×10 A
T
rises at a rate of 1µA/°C.
sets the level at which the
4
T
( )
is 5mA. For the ISL6292 in
100
is the current from the
O
T
C
has no impact on the
I
R
Temperature
I
SEN
MIN
I
T
MIN
is set in
because
(EQ. 6)
MIN
MIN
is
ISL6292
2.8V Bias Voltage
The ISL6292 provides a 2.8V voltage for biasing the internal
control and logic circuit. This voltage is also available for
external circuits such as the NTC thermistor circuit. The
maximum allowed external load is 2mA.
NTC Thermistor
The ISL6292 uses two comparators (CP2 and CP3) to form a
window comparator, as shown in Figure 22. When the TEMP
pin voltage is “out of the window,” determined by the V
and V
condition. When the temperature returns to the set range, the
charger re-starts a charge cycle. The two MOSFETs, Q1 and
Q2, produce hysteresis for both upper and lower thresholds.
The temperature window is shown in Figure 21.
As the TEMP pin voltage rises from low and exceeds the 1.4V
threshold, the under temperature signal rises and does not
clear until the TEMP pin voltage falls below the 1.2V falling
threshold. Similarly, the over-temperature signal is given when
the TEMP pin voltage falls below the 0.35V threshold and does
V
FIGURE 22. THE INTERNAL AND EXTERNAL CIRCUIT FOR
TMAX+
V
V
V
TMAX
FIGURE 21. CRITICAL VOLTAGE LEVELS FOR TEMP PIN
TMIN-
TMIN
Under
Temp
Battery
Removal
Over
Temp
TMAX
(0.406V)
(0.35V)
(1.4V)
(1.2V)
Under
Temp
Temp
Over
2.8V
0V
ISL6292
, the ISL6292 stops charging and indicates a fault
CP1
CP2
CP3
THE NTC INTERFACE
+
+
+
-
-
-
V
TMAX
V
V
RMV
TMIN
To TEMP Pin
Q1
Q2
2.8V
R3
75K
R5
4K
R4
25K
R1
40K
R2
60K
V2P8
TEMP
GND
December 17, 2007
R
Voltage
R
T
TEMP
TMIN
U
Pin
FN9105.9