DATASHEET
ISL6292B
FN9139
Rev.2.00
Nov.2.2020
Li-ion/Li Polymer Battery Charger
The ISL6292B uses dual-mode charge technology to
minimize the heat in a linear charger. The ISL6292B is a
modification of the original ISL6292 and is optimized for
cellular phone travel charger applications. The low-heat
generation feature of the dual-mode charger enables the
charger IC to be placed inside the connector of the travel
charger to completely remove the influence of the adapter
cable on the charging performance.
Working with a current-limited ac/dc converter, the dualmode charger charges a Li-ion battery with the same current
profile as a traditional linear charger. The constant charge
current is determined by the current limit of the ac/dc
converter. The constant output voltage is fixed at 4.2V. When
the battery voltage is below 2.8V, the charger preconditions
the battery with a low trickle-charge current. The charge
status is indicated by a tri-color LED. A safety timer prevents
charging a dead battery for an excessively long period.
The ISL6292B also features a thermal foldback function that
automatically reduces the charge current when the internal
die temperature exceeds a 100°C limit to prevent further
temperature rise. This function removes the concern of
thermal failure in the targeted space-limited applications. An
ambient temperature monitoring circuit allows users to set
two separate temperature limit levels, one for during charge
and one for not during charge. The thermally-enhanced QFN
package further improves the thermal performance of the
ISL6292B in space-limited applications.
Related Literature
For a full list of related documents, visit our website
• ISL6292B product page
Features
• Complete Charger for Single-Cell Li-ion Batteries
• Integrated Pass Element and Current Sensor
• No External Blocking Diode Required
• Very Low Thermal Dual-Mode Operation
• 1% Voltage Accuracy with Remote Sense
• Programmable Current Limit up to 1.5A
• Programmable End-of-Charge Current
• Programmable Safety Timer
• Drives a Tri-Color LED
• Charge Current Thermal Foldback
• NTC Thermistor Interface for Battery Temperature Monitor
• Two-Level Ambient Temperature Setting
• Guaranteed to Operate at 2.65V After Start-Up
• Ambient Temperature Range: -20°C to 70°C
• Thermally-Enhanced QFN Packages
• QFN Package:
- Near Chip Scale Package footprint, which improves
PCB efficiency and has a thinner profile
• Pb-Free Available (RoHS Compliant)
Applications
• Handheld Devices including Medical Handhelds
• PDAs, Cell Phones and Smart Phones
• Portable Instruments, MP3 Players
• Self-Charging Battery Packs
• Stand-Alone Chargers
• USB Bus-Powered Chargers
FN9139 Rev.2.00
Nov.2.2020
Page 1 of 12
ISL6292B
Overview
Typical Application
Input
C1
T o Battery
BAT
VIN
BAT -
V2P9
VSEN
R3
R1
C2
TEMP
D2
D1
RS
R5
R4
R2
DT
ID
EN
C4
ISL6292B
RT
C TIM E
TIME
RED
R IREF
IREF
GRN
R IM IN
GND
C1, C3:
C2, C4:
CTIME :
D1, D2:
RIREF :
RIMIN :
BAT +
C3
IMIN
1F X5R ceramic capacitor
0.1F X5R ceramic capacitor
22nF X5R or better timing capacitor
dual-color (red and green) LED in one package
80k, 1%
133k, 1%
R1: 41.2k, 1%
R2: TBD, value dependent on the T (2.3k for 20°C)
RT: ECTH-160808-103-J-3800HT, 10k at 25°C, 5%
RS: 1.33k, 1%
R3: 10k, 5% (R3 and C4 are for improving ESD protection)
R4, R5: 330, 5%
Block Diagram
Q M AIN
VIN
IMIN
Input_OK
VMIN
V POR
+
+
+
VA
-
I M IN
RIM IN
-
-
CHRG
Curre nt
Refe re nce s
V IN
+
+
CA
-
IR
VR ECHRG
ISEN
-
RIREF
100000:1
Curre nt
Mirror
VCH
Q SEN
IT
IREF
V2P9
Re fe re nce s
Te mpe ra ture
Monitoring
VPOR
C1
BAT
VSEN
100mV
VCH
+
Trickle /Fa st
I SEN
-
MIN_I
+
NTC
Interfa ce
GND
FN9139 Rev.2.00
Nov.2.2020
OSC
VRECHRG
Re cha rge
Unde rTe mp
DT
TIME
VM IN
+
V2P
8
TEMP
-
Minba t
LOGIC
Ove rTe mp
RED
GRN
COUNTER
Input_OK
EN
Page 2 of 12
ISL6292B
Ordering Information
PART NUMBER
(Notes 2, 3)
PART MARKING TEMP. RANGE (°C)
TAPE AND REEL
(Units) (Note 1)
PACKAGE
(RoHS Compliant)
PKG. DWG. #
ISL6292BCRZ
62 92BCRZ
-20 to 70
-
16 Ld 4x4 QFN
L16.4x4
ISL6292BCRZ-T
62 92BCRZ
-20 to 70
6k
16 Ld 4x4 QFN
L16.4x4
NOTES:
1. See TB347 for details about reel specifications.
2. These Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte tin
plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Pb-free
products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J-STD-020.
3. For Moisture Sensitivity Level (MSL), see the ISL6292B device page. For more information about MSL, see TB363.
EN
Pin Configuration
VIN
VIN
BAT
BAT
ISL6292B TOP VIEW
16
15
14
13
EN is the enable logic input. Connect the EN pin to LOW to
enable the charger or leave it floating to disable the charger.
This pin is pulled up to 2.9V when left floating.
10 IMIN
9 IREF
5
6
7
8
V2P9
RED 3
TIME 4
This is the programming input for the constant charging
current in a linear charger. In the typical application of a
dual-mode charger, the IREF pin programs the trickle charge
current as well as the protection current level.
EN
IREF
11 TEMP
DT
12 VSEN
GRN 2
GND
VIN 1
Pin Description
VIN
VIN is the input power source. Connect to a wall adapter.
RED, GRN
RED and GRN are two open-drain outputs to drive a red and
a green LED in the same package. The RED and the GRN
pins are guaranteed to be capable of sinking at least 5mA
current.
TIME
The TIME pin determines the oscillation period by
connecting a timing capacitor between this pin and GND.
The oscillator provides a time reference for the charger.
GND
IMIN
IMIN is the programmable input for the end-of-charge
current.
TEMP
TEMP is the input for an external NTC thermistor.
DT
DT is the input to set the temperature difference before and
after the charging starts. This pin can also be used as an
indication whether or not the charger is charging.
VSEN
VSEN is the battery voltage sensing input. This pin allows
remote sense of the battery pack voltage.
BAT
BAT is the charger output.
GND is the connection to system ground.
V2P9
This is a 2.9V untrimmed voltage output. This pin outputs a
2.9V voltage source when the input voltage is above POR
threshold, independent on the EN pin input. The V2P9 pin
can be used as an indication for adapter presence.
FN9139 Rev.2.00
Nov.2.2020
Page 3 of 12
ISL6292B
Absolute Maximum Ratings
Thermal Information
Supply Voltage (VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to 7V
Output Pin (BAT, VSEN, RED, GRN, DT) . . . . . . . . . . . -0.3 to 5.5V
Signal Pin (EN, TIME TEMP, IREF, IMIN, V2P9) . . . . . . -0.3 to 3.2V
Charge Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6A
ESD Rating
Human Body Model (Per MIL-STD-883 Method 3015.7) . . .3500V
Machine Model (Per EIAJ ED-4701 Method C-111) . . . . . . . .200V
Thermal Resistance (Notes 1, 2)
JA (°C/W)
JC (°C/W)
4x4 QFN Package . . . . . . . . . . . . . . . .
41
4
Maximum Junction Temperature (Plastic Package) . . . . . . . . 150°C
Maximum Storage Temperature Range. . . . . . . . . . . -65°C to 150°C
Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300°C
Recommended Operating Conditions
Ambient Temperature Range . . . . . . . . . . . . . . . . . . . .-20°C to 70°C
Supply Voltage, VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3V to 6.5V
Recommended Charge Current. . . . . . . . . . . . . . . . 400mA to 1.5A
CAUTION: Stresses above those listed in Absolute Maximum Ratings can cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTES:
4. JA is measured in free air with the component mounted on a high-effective thermal conductivity test board with direct attach features. See
TB379.
5. JC, case temperature location is at the center of the exposed metal pad on the package underside. See TB379.
Electrical Specifications
Typical values are tested at VIN = 5V and 25°C Ambient Temperature, maximum and minimum values are guaranteed over -10°C to 70°C Ambient
Temperature with a supply voltage in the range of 4.3V to 6.5V, unless otherwise noted.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Rising VIN Threshold
3.0
3.4
4.0
V
Falling VIN Threshold
2.3
2.4
2.7
V
VIN floating or EN pin is floating
-
-
3.0
A
BAT Pin floating, EN = LOW
-
0.5
-
mA
4.158
4.20
4.242
V
-
190
-
mV
POWER-ON RESET
STANDBY CURRENT
VBAT Pin Sink Current
ISTANDBY
VIN Pin Supply Current
IVIN
VOLTAGE REGULATION
Output Voltage
VCH
Dropout Voltage
VBAT = 3.7V, ICHARGE = 0.65A
CHARGE CURRENT
Charge/Protection Current (Note 3)
ICHARGE
RIREF = 80k, VBAT = 3.7V, VIN = 5V
0.9
1.0
1.1
A
Trickle Charge Current
ITRICKLE
RIREF = 80k, VBAT = 2.0V, VIN = 5V
85
110
135
mA
RIMIN = 133k
40
60
80
mA
VRECHRG
3.85
4.00
4.13
V
VMIN
2.7
2.8
3.2
V
1.44
1.50
1.58
V
-
214
-
mV
0.35
0.38
0.405
V
-
51.4
-
mV
RDT
-
30
100
TFOLD
85
100
115
°C
End-of-Charge Threshold
RECHARGE THRESHOLD
Recharge Voltage Threshold
TRICKLE CHARGE THRESHOLD
Trickle Charge Threshold Voltage
BATTERY TEMPERATURE MONITORING
Low Temperature Threshold
VTMIN
V2P9 = 3.0V
Low Temperature Hysteresis (Note 4)
High Temperature Threshold
VTMAX
High Temperature Hysteresis (Note 4)
DT Pin MOSFET On Resistance
Charge Current Foldback Threshold (Note 4)
FN9139 Rev.2.00
Nov.2.2020
V2P9 = 3.0V
Page 4 of 12
ISL6292B
Electrical Specifications
Typical values are tested at VIN = 5V and 25°C Ambient Temperature, maximum and minimum values are guaranteed over -10°C to 70°C Ambient
Temperature with a supply voltage in the range of 4.3V to 6.5V, unless otherwise noted. (Continued)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
-
100
-
mA/°C
2.4
3.0
3.6
ms
EN Input Low
-
-
0.8
V
EN Pin External Pull Down to Disable
-
-
50
k
Current Foldback Gain (Note 4)
TEST CONDITIONS
GFOLD
OSCILLATOR
Oscillation Period
TOSC
CTIME = 15nF
LOGIC INPUT AND OUTPUT
RED Sink Current
Pin Voltage = 0.8V
5
-
-
mA
GRN Sink Current
Pin Voltage = 0.8V
5
-
-
mA
NOTES:
6. The actual current may be lower due to the thermal foldback.
7. Guaranteed by design, not a tested parameter.
FN9139 Rev.2.00
Nov.2.2020
Page 5 of 12
ISL6292B
Flow Chart
Anytime POR
and Enable
occurs
TEMP fault removed
TEMP FAULT
Charger: OFF
LED: YELLOW
TRICKLE CHARGE
Charger: ON
LED: RED
TEMP fault
TEMP fault
VBAT < 2.8V when 1/8 TIMEOUT
completes
TIMEOUT FAULT
Charger: OFF
LED: YELLOW
VBAT > 2.8V before 1/8 TIMEOUT
completes
FAST CHARGE
Charger: ON
LED: RED
TIMEOUT
completes and
VBAT < VRECHRG
VBAT > VRECHRG and ICHG < IMIN
and
TIMEOUT not completed
TEMP fault
CHARGE COMPLETES BUT NOT
TERMINATES
Charger: ON
LED: GREEN
TIMEOUT
completes
TEMP fault
removed
TEMP FAULT
Charger: OFF
LED: YELLOW
CHARGE TERMINATES
Charger: OFF
LED: GREEN
TIMEOUT
completes and
VBAT > VRECHRG
CHARGE TERMINATES
Charger: OFF
LED: GREEN
TEMP fault
VBAT < VRECHRG
TEMP fault
removed
TEMP FAULT
Charger: OFF
LED: YELLOW
RECHARGE
Charger: ON
LED: GREEN
TIMEOUT completes
TEMP fault
FN9139 Rev.2.00
Nov.2.2020
Page 6 of 12
ISL6292B
Theory of Operation
The ISL6292B is based on the Renesas dual-mode charging
technology. The dual-mode technology generates very low
heat, which enables the charger to be used in space-limited
applications.
To take advantage of the low-heat feature, a current-limited
ac/dc converter is required as the power supply to the
charger. The current-limited supply has the I-V
characteristics shown in Figure 1. The supply is a dc source
before the load current reaches the limited current ILIM.
Once the current limit is reached, the supply current cannot
increase further; instead, the supply voltage falls. The
current-limited supply is equivalent to a voltage source with
an equivalent output impedance or a current source,
depending on the region it operates at, as shown in Figure 1.
The ISL6292B charges a battery with the traditional constant
current/constant voltage (CC/CV) profile. The constant
current is determined by the current limit ILIM of the supply
during the constant-current charge mode. To ensure dualmode operation, the current protection level set by the IREF
pin should be higher than ILIM. In the constant-voltage
charge mode, the battery voltage is regulated at 4.2V. When
the battery voltage is below the VMIN given in the Electrical
Specification, the charger preconditions the battery using
trickle charge mode. The trickle-charge current is 10% of the
protection current level programmed by the IREF pin.
Figure 2 shows the typical waveforms in a charge cycle of
the dual mode operation. When the battery is below VMIN,
the charge current is 10% of IREF set by the IREF pin. Since
the charge current is much less than the ILIM, the ac/dc
converter operates in the voltage source region. Once the
battery voltage exceeds VMIN, the charger starts to fully turn
on the internal P-channel power MOSFET. The ac/dc
converter operates in the current-limited region and its
voltage is pulled down to a level slightly higher than the
battery voltage. As shown in Figure 2, the charge current is
ILIM and is lower than IREF. As the battery voltage reaches
the 4.2V VCH, the charge current starts to decrease. The
ac/dc supply moves out of the current-limit region and
becomes a voltage source again. When the charge current
reaches a programmable end-of-charge (EOC) level set by
the IMIN pin, the charger sends out an EOC indication. The
real termination of the charger happens at the end of a total
charge time set by the TIME pin.
The power dissipation is also shown in Figure 2. The power
dissipation in both the trickle mode and the constant-current
(CC) mode are very low. The possible peak power occurs at
the transition from the CC mode to the constant-voltage (CV)
mode. This peak power is much lower than the peak power
normally seen in a linear charger and can be further reduced
by properly designing the ac/dc converter. One simple
approach is to design the ac/dc converter output voltage just
high enough to fully charge the battery (normally lower than
5V). More information can be found in the ISL6292
datasheet. To ensure the thermal safety, the ISL6292B has
an internal thermal fold-back function that automatically
reduces the charge current if the internal temperature
typically rises above 100°C.
The ISL6292B offers many other features. The trickle
current, the CC charge current, and the end-of-charge
(EOC) current are all programmable. A thermal foldback
function monitors the internal temperature and reduces the
charge current when the internal temperature rises above
100°C to prevent further temperature rise. A safety timer
sets the charge time limit for both trickle mode and fast mode
charge. When the battery voltage drops after the charge
cycle terminates, the charger automatically starts recharging
the battery to full. Two indication pins are designed to drive a
tri-color LED (a red and a green LED in the same package).
A simple thermistor circuit interface allows the user to set a
different level of ambient temperature before and after the
charger starts. All these features are described in detail in
the Application Information section.
Trickle
Mode
VIN
V CH
Constant
Current Mode
Constant
Voltage Mode
Inhibit
Input Voltage
Battery Voltage
V M IN
V NL
C
r O = (VNL - VFL )/ILIM
VFL
B
IREF
ILIM
Charge Current
rO
VNL
IREF /10
I LIM
A
ILIM
FIGURE 1. THE I-V CHARACTERISTICS OF THE CURRENTLIMITED AC/DC CONVERTER.
FN9139 Rev.2.00
Nov.2.2020
P1
P2
Power Dissipation
TIMEOUT
FIGURE 2. TYPICAL CHARGE CURVES USING A CURRENTLIMITED ADAPTER.
Page 7 of 12
ISL6292B
Applications Information
EOC Current and RIMIN Selection
Power-On Reset (POR)
The EOC current is programmed by the IMIN pin and can be
calculated by the following equation:
The ISL6292B has a 3.4V rising POR threshold. Before the
input voltage reaches the POR threshold, the 2.9V V2P9 pin
outputs 0V and the charger is disabled. Once the POR
threshold is reached, the V2P9 pin outputs 2.9V, the opendrain MOSFET on the DT pin is turned on, and the ambient
temperature monitoring circuit starts to function. After a
delay and after the input voltage rises above the battery
voltage, the charger control circuit starts to work and the DT
pin impedance becomes high. Figure 3 shows the sequence
of the events at power on. The POR has a falling threshold
of 2.4V typically. At power on, all counters are reset to zero.
Charge Current and RIREF Selection
When the ISL6292B is used as a traditional linear charger,
the RIREF sets the constant charge current. The trickle
charge current is 10% of the CC current IREF . When working
with a current-limited supply, the CC current is determined
by the supply limited current ILIM. IREF needs to be
programmed higher than ILIM and is used as an overcurrent
protection. Taking into account the tolerance of both the ILIM
and IREF, it is recommended the IREF be programmed at
least 30% higher than the ILIM. IREF can be found by the
following equation:
5
0.8V
I REF = ----------------- 10 A
R IREF
(EQ. 1)
(EQ. 2)
The ISL6292B has a comparator with 100mV offset voltage
to ensure the input voltage is higher than the battery voltage
before charging starts (see the Block Diagram). This
condition requires ILIM be higher than 400mA. The upper
limit for ILIM is 1.5A.
VIN
POR
(EQ. 3)
The EOC current has a programming range up to 400mA.
To qualify as an EOC condition, the charge current needs to
drop below the IMIN level and stay below the IMIN level for
more than three to four cycles of the internal oscillator;
additionally, the battery voltage rises above the recharge
threshold given in the Electrical Specification table.
Internal Oscillator
The internal oscillator establishes a timing reference. The
oscillation period is programmable with an external timing
capacitor, CTIME, as shown in Typical Applications. The
oscillator charges the timing capacitor to 1.5V and then
discharges it to 0.5V in one period, both with 10A current.
The period TOSC is:
6
T OSC = 0.2 10 C TIME
Total Charge Time and CTIME Selection
C TIME
TIMEOUT = 14 -----------------1nF
minutes
VIN
POR
Th re sh o ld
V2P9
Ch arg e
Cycle
(EQ. 5)
Ch arg e
Cycle
DT
Imp e d .
M IN
V2P9
15 Cycle s to
1/8 TIM EOUT
GRN
DT
Imped
VBAT
Charger
Start
I CHG
V RECHRG
2.8V V M IN
15
Cycle s
I M IN
t0
FN9139 Rev.2.00
Nov.2.2020
(EQ. 4)
A 1nF capacitor results in a 0.2ms oscillation period. The
accuracy of the period is mainly dependent on the accuracy
of the capacitance and the internal current source.
RED
FIGURE 3. EVENT SEQUENCE AT POWER UP
sec onds
The total charge time for the CC mode and CV mode is
limited to a length of TIMEOUT, which can be found by:
The trickle charge current is 10% of IREF, that is,
4
0.8V
I Trickle = ----------------- 10 A
R IREF
4
0.8V
I MIN = ---------------- 10 A
R IMIN
t1 t2 t3
t4
t5
t6 t7
FIGURE 4. OPERATION WAVEFORMS
Page 8 of 12
t8
ISL6292B
BAT
VSEN
2.9V
R1
10
Under
Temp CP1
R2
R1
100K
VTM IN
+
V2P9
RU
R2
75K
To TEMP Pin
TEMP
-
VA
+
Q1
VREF
Enable
R3
Q1
Over
Temp
CP2
+
R3
25K
V TM AX
Q2
RT
R4
4K
DT
FIGURE 5. THE INTERNAL VOLTAGE FEEDBACK CIRCUIT
Q3
CHG
CTIME is the timing capacitor shown in the Typical
Application circuit. A 1nF capacitor leads to 14 minutes of
TIMEOUT. For example, a 15nF capacitor sets the
TIMEOUT to be 3.5 hours. The charger is terminated when
the TIMEOUT is reached.
The trickle mode charge has a time limit of 1/8 TIMEOUT. If
the battery voltage does not reach VMIN within that limit, a
TIMEOUT fault is issued and the charger latches up. The
charger stays in trickle mode for at least 15 cycles of the
internal oscillator and, at most, 1/8 of TIMEOUT.
GND
RD
FIGURE 6. THE INTERNAL AND EXTERNAL CIRCUIT FOR
THE NTC INTERFACE
TABLE 1. LED INDICATION SUMMARY
STATUS
RED GRN
INDICATION
Charging
L
H
Red
Full Charge (EOC), or recharging
H
L
Green
Recharge Threshold
Trickle TIMEOUT Error
L
L
Yellow (Latched)
The charger terminates when the TIMEOUT limit expires.
After the termination, if the battery is below the recharge
threshold given in the Electrical Specification table, the
charger starts a re-charge cycle.
Over/Under Ambient Temperature
L
L
Yellow
No Battery
H
H
Off
LED Indications
RED and GRN are two open-drain outputs that directly drive
a tri-color LED. At the moment when the power is applied or
when the charger is enabled through the EN pin, the charger
starts to charge and the RED indication pin outputs a low
impedance to drive a red LED. Once the charge finishes
(either when the EOC condition is qualified or when the
TIMEOUT completes), the GRN pin turns on to drive a green
LED and the red LED is off. The green LED remains on
unless the input power is recycled, or when the EN pin is
toggled, or a fault case happens. When a recharge occurs,
the indication remains in green.
When a fault case happens, both the RED and the GRN pins
are on to indicate a yellow color. If the FAULT is a TIMEOUT
fault, the yellow indication is latched and can only be reset
through the EN pin or the input power. If the FAULT is an
ambient temperature FAULT, the charger restarts after the
fault condition is removed. When not powered or when not
enabled, both LEDs are off. Table 1 summarizes the LED
indications.
FN9139 Rev.2.00
Nov.2.2020
VSEN Pin
The VSEN pin allows remote sensing of the battery voltage
to minimize the resistive voltage drop between the charger
output and the battery positive terminal. Figure 5 shows the
internal voltage feedback circuit. In applications that the
remote sense pin goes through a connector, a local lowvalue resistor is recommended, as the R1 shown in Figure 5,
in case the connector has bad contact. The sum of R2 and
R3 is 75k, therefore, a 10 R1 is negligible in output
voltage accuracy.
Ambient Temperature Sensing
The TEMP pin is used to set the ambient temperature range
that allows charging the battery. Typically, an NTC (negative
temperature coefficient) resistor is mounted on the printed
circuit board (PCB) to monitor the ambient temperature. Due
to the self-heating of the PCB during charging, the ISL6292B
provides the DT pin to set a higher temperature threshold
after the charger starts.
Figure 6 shows the internal circuit for the ambient
temperature sensing function. The two comparators form a
window comparator whose high-threshold is VTMIN and lowthreshold is VTMAX. These two thresholds are given in the
Electrical Specifications. The two MOSFETs (Q1 and Q2)
Page 9 of 12
ISL6292B
NOTCHARGE
V2P9
V2P9
45 oC
40 oC
TEMP
TEMP
Less than 2 °C
RT
RT
NOTCHARGE
45 C + T
RU
RU
CHARGE
o
0 oC
-5 oC
DT
RD
RQ3
GND
(A)
GND
(B)
FIGURE 7. EQUIVALENT CIRCUITS FOR THE NTC DIVIDER
(A) BEFORE CHARGING STARTS
(B) DURING CHARGING.
create a hysteresis for each comparator respectively. The
DT pin is shorted to GND via the internal Q3 MOSFET when
the charger is not charging, resulting in the equivalent circuit
shown in Figure 7 (A). The on-resistance of Q3 is typically
50 and is negligible compared to the external resistors.
When the charger starts to charge, Q3 is turned off to set a
higher temperature range determined by the external
resistor RD. The equivalent circuit is shown in Figure 7 (B).
The DT pin allows the user to set up a higher shut down
ambient temperature after the charger starts up.
The selection of RU and RT uses the same procedure
described in the ISL6292 datasheet. The selection RD
follows the following equation:
RD = RT,@45°C - RT,@(45°C + T)
where RT,@45°C is the thermistor resistance at 45°C and the
RT,@(45°C + T) is the resistance at 45°C + T. Figure 8
shows the temperature windows before, during, and after
charging. Before and after charging, the temperature window
is -5°C to 45°C with 5°C hysteresis. During charging, the
high temperature limit changes to 45°C + T. If this limit is
exceeded, the charger is stopped and the temperature has
to come back to below 40°C for the charging to be allowed
again. The low temperature limit is also increased. However,
the RD typically has a much lower resistance than the NTC
at low temperature, therefore, the influence on the
temperature threshold is not as much as at high
temperature. Typically, the low temperature threshold is
raised by less than 2°C, as shown in Figure 8.
Charge Current Thermal Foldback
The thermal foldback function monitors the die temperature
and reduces the charge current when the die temperature
rises above 100°C to prevent further temperature rise. The
charge current reduces at a rate of 100mA/°C after
exceeding 100°C. For a charger with the constant charge
current set at 1A, the charge current is reduced to zero when
FN9139 Rev.2.00
Nov.2.2020
FIGURE 8. BOARD TEMPERATURE MONITORING WHEN
THE CHARGE IS NOT CHARGING, THE
TEMPERATURE WINDOW IS -5°C AND 45°C.
ONCE THE CHARGER STARTS, THE
TEMPERATURE WINDOW IS 1.X°C TO 45°C+ T.
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 IMIN
because of the thermal foldback. For some extreme cases if
that does happen, the charger does not indicate end-ofcharge unless the battery voltage is already above the
recharge threshold.
2.9V Bias Voltage
The ISL6292B provides a 2.9V 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.
EN Pin
The EN pin allows direct interface to the battery ID pin of a
battery pack. The battery ID pin is connected with a resistor
of a value less than 27k to ground inside the battery pack.
When the battery is not attached, the EN pin is pulled up by
an internal source to the V2P9 pin to disable the charger.
The 2.9V internal regulator is on as long as the input power
is applied, independent of the EN input. Table 2 summarizes
the status of each pin when the IC is disabled.
TABLE 2. SUMMARY OF PIN BEHAVIOR WHEN THE IC IS
DISABLED BY THE EN PIN
PIN
BEHAVIOR
V2P9
Outputs 2.9V.
RED
High impedance
GRN
High impedance
DT
Low impedance
IREF
Outputs 0.8V
IMIN
Outputs 0.8V
TEMP
The temperature monitoring circuit remains functioning.
Page 10 of 12
ISL6292B
Board Layout Recommendations
The ISL6292B is targeted for space-limited applications. In
order to maximize the current capability, it is very important that
the exposed pad under the package is properly soldered to the
board and is connected to other layers through thermal vias.
More thermal vias and more copper attached to the exposed
pad usually result in better thermal performance. On the other
hand, the number of vias is limited by the size of the pad. The
exposed pads for the 4x4 QFN package are able to have 5
vias. As much copper as possible should be connected to the
exposed pad to minimize the thermal impedance. Refer to the
ISL6292B evaluation board for layout examples.
Revision History
REV.
DATE
DESCRIPTION
2.0
Nov.2.20
Removed packaging features bullet.
Updated Related Literature section
Updated Ordering Information table removing retired parts, adding tape and reel information, and updating/adding
notes.
Added Revision History section
Updated POD L16.4x4 to the latest revision, the following are the list of changes:
- Changed POD into new QFN format.
FN9139 Rev.2.00
Nov.2.2020
Page 11 of 12
ISL6292B
Package Outline Drawing
For the most recent package outline drawing, see L16.4x4.
L16.4x4
16 Lead Quad Flat No-Lead Plastic Package
Rev 6, 02/08
4X 1.95
4.00
12X 0.65
A
B
13
6
PIN 1
INDEX AREA
6
PIN #1 INDEX AREA
16
1
4.00
12
2 . 10 ± 0 . 15
9
4
0.15
(4X)
5
8
TOP VIEW
0.10 M C A B
+0.15
16X 0 . 60
-0.10
4 0.28 +0.07 / -0.05
BOTTOM VIEW
SEE DETAIL "X"
0.10 C
1.00 MAX
( 3 . 6 TYP )
(
2 . 10 )
C
BASE PLANE
SEATING PLANE
0.08 C
SIDE VIEW
( 12X 0 . 65 )
( 16X 0 . 28 )
C
0 . 2 REF
5
( 16 X 0 . 8 )
0 . 00 MIN.
0 . 05 MAX.
DETAIL "X"
TYPICAL RECOMMENDED LAND PATTERN
NOTES:
1. Dimensions are in millimeters.
Dimensions in ( ) for Reference Only.
2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994.
3. Unless otherwise specified, tolerance : Decimal ± 0.05
4. Dimension b applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
5. Tiebar shown (if present) is a non-functional feature.
6. The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 identifier may be
either a mold or mark feature.
FN9139 Rev.2.00
Nov.2.2020
Page 12 of 12
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