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ISL9203A
Data Sheet February 14, 2007 FN6430.0
Li-ion/Li Polymer Battery Charger
The ISL9203A is an integrated single-cell Li-ion or Li-polymer battery charger capable of operating with an input voltage as low as 2.4V. This charger is designed to work with various types of AC adapters. The ISL9203A operates as a linear charger when the AC adapter is a voltage source. The battery is charged in a CC/CV (constant current/constant voltage) profile. The charge current is programmable with an external resistor up to 1.5A. The ISL9203A can also work with a current-limited adapter to minimize the thermal dissipation, in which case the ISL9203A combines the benefits of both a linear charger and a pulse charger. The ISL9203A features charge current thermal foldback to guarantee safe operation when the printed circuit board is space limited for thermal dissipation. Additional features include preconditioning of an over-discharged battery and thermally enhanced DFN package.
Features
* Complete Charger for Single-Cell Li-ion Batteries * Very Low Thermal Dissipation * Integrated Pass Element and Current Sensor * No External Blocking Diode Required * 1% Voltage Accuracy * Programmable Current Limit up to 1.5A * Charge Current Thermal Foldback * Accepts Multiple Types of Adapters * Guaranteed operation down to VIN = 2.65V after start up * Ambient Temperature Range: -20C to +70C * Thermally-Enhanced DFN Packages * Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
* Handheld Devices including Medical Handhelds * PDAs, Cell Phones and Smart Phones * Portable Instruments, MP3 Players
Typical Application Circuit
5V INPUT C1 R1 VIN VBAT
C2
* Self-Charging Battery Packs * Stand-Alone Chargers * USB Bus-Powered Chargers
ISL9203A
VSEN STATUS V2P8 EN TIME IREF GND R IREF C3
FLOATING TO ENABLE
Related Literature
* Technical Brief TB363 "Guidelines for Handling and Processing Moisture Sensitive Surface Mount Devices (SMDs)" * Technical Brief TB379 "Thermal Characterization of Packaged Semiconductor Devices" * Technical Brief TB389 "PCB Land Pattern Design and Surface Mount Guidelines for QFN Packages"
CTIME
Ordering Information
PART NUMBER PART (Note) MARKING ISL9203ACRZ 03ACZ TEMP. RANGE (C) -20 to +70 PACKAGE (Pb-free) PKG DWG. #
Pinout
ISL9203A (10 LD 3x3 DFN) TOP VIEW
10 Ld 3x3 DFN L10.3x3
VIN NC STATUS TIME GND
1 2 3 4 5
10 VBAT 9 8 7 6 VSEN IREF V2P8 EN
ISL9203ACRZ-T 10 Ld 3x3 DFN Tape and Reel NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil 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.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright (c) Intersil Americas Inc. 2007. All Rights Reserved. All other trademarks mentioned are the property of their respective owners.
ISL9203A
Absolute Maximum Ratings
Supply Voltage (VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to 7V Output Pin Voltage (BAT, VSEN, V2P8). . . . . . . . . . . . -0.3V to 5.5V Signal Input Voltage (TIME, IREF). . . . . . . . . . . . . . . . -0.3V to 3.2V Output Pin Voltage (STATUS) . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V Charge Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6A ESD Rating Human Body Model (Per MIL-STD-883 Method 3015.7) . . .4500V Machine Model (Per EIAJ ED-4701 Method C-111) . . . . . . . .200V
Thermal Information
Thermal Resistance (Typical, Notes 1, 2) JA (C/W) JC (C/W) 3x3 DFN Package . . . . . . . . . . . . . . . . 46 4 Maximum Junction Temperature (Plastic Package) . . . . . . . +150C Maximum Storage Temperature Range . . . . . . . . . .-65C to +150C Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . +300C
Recommended Operating Conditions
Ambient Temperature Range . . . . . . . . . . . . . . . . . . .-20C to +70C Supply Voltage, VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3V to 6.5V
CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may 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. +150C max junction temperature is intended for short periods of time to prevent shortening the lifetime. Operation close to +150C junction may trigger the shutdown of the device even before +150C, since this number is specified as typical.
NOTES: 1. JA is measured in free air with the component mounted on a high effective thermal conductivity test board with "direct attach" features. See Tech Brief TB379. 2. JC, "case temperature" location is at the center of the exposed metal pad on the package underside. See Tech Brief TB379.
Electrical Specifications
Typical values are tested at VIN = 5V and +25C Ambient Temperature, maximum and minimum values are guaranteed over 0C to +70C Ambient Temperature with a supply voltage in the range of 4.3V to 6.5V, unless otherwise noted. SYMBOL TEST CONDITIONS MIN TYP MAX UNITS
PARAMETER POWER-ON RESET Rising VIN Threshold Falling VIN Threshold STANDBY CURRENT VBAT Pin Sink Current VIN Pin Supply Current VIN Pin Supply Current VOLTAGE REGULATION Output Voltage Dropout Voltage CHARGE CURRENT Constant Charge Current (Note 3) Constant Charge Current Trickle Charge Current Trickle Charge Current End-of-Charge Threshold End-of-Charge Threshold RECHARGE THRESHOLD Recharge Voltage Threshold
3.0 2.3
3.4 2.4
4.0 2.65
V V
ISTANDBY IVIN IVIN
VIN floating or EN = LOW VBAT floating and EN pulled low VBAT floating and EN floating
-
30 1
3.0 250 2
A A mA
VCH VBAT = 3.7V, Charge current = 1A
4.158 -
4.20 320
4.242 550
V mV
ICHARGE ICHARGE ITRICKLE ITRICKLE IMIN IMIN
RIREF = 80k, VBAT = 3.7V RIREF = 1.21M, VBAT = 3.7V RIREF = 80k, VBAT = 2.0V RIREF = 1.21M, VBAT = 2.0V RIREF = 80k RIREF = 1.21M
0.9 33 85 2 85 2
1.0 66 110 7 110 -
1.1 100 135 15 135 30
A mA mA mA mA mA
VRECHRG
3.85
4.00
4.10
V
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ISL9203A
Electrical Specifications
Typical values are tested at VIN = 5V and +25C Ambient Temperature, maximum and minimum values are guaranteed over 0C to +70C Ambient Temperature with a supply voltage in the range of 4.3V to 6.5V, unless otherwise noted. (Continued) SYMBOL TEST CONDITIONS MIN TYP MAX UNITS
PARAMETER TRICKLE CHARGE THRESHOLD Trickle Charge Threshold Voltage V2P8 PIN VOLTAGE V2P8-Pin Voltage TEMPERATURE MONITORING Charge Current Foldback Threshold (Note 4) Current Foldback Gain (Note 4) OSCILLATOR Oscillation Period LOGIC OUTPUTS STATUS Logic Low Sink Current STATUS Leakage Current EN Input Logic High EN Input Logic Low EN Pin Current When Driven Low NOTES:
VMIN
2.1
2.3
2.5
V
VV2P8
2.7
2.9
3.1
V
TFOLD GFOLD
-
100 100
-
C mA/C
TOSC
CTIME = 15nF
2.4
3.0
3.6
ms
Pin Voltage = 0.8V VVIN = VSTATUS = 5V
5 2.0 -
-
1 3.3 0.8 100
mA A V V A
3. The accuracy includes all errors except the programming resistance tolerance. The actual charge current may be affected by the thermal foldback function if the thermal dissipation capability is not enough or by the on resistance of the power MOSFET if the charger input voltage is too close to the output voltage. 4. Guaranteed by characterization.
Typical Operating Performance
4.2015 4.2010 4.2005 VBAT (V) 4.2000
The test conditions for the Typical Operating Performance are: VIN = 5V, TA = +25C, RIREF = RIMIN = 80k, VBAT = 3.7V, unless otherwise noted.
4.210 4.208
RIREF = 40k VBAT (V)
4.206 4.204 4.202 4.200 4.198 4.196
CHARGE CURRENT = 50mA
4.1995 4.1990 4.1985 4.1980 4.1975 0 0.3 0.6 0.9 1.2 1.5 CHARGE CURRENT (A)
4.194 4.192 4.190 0 20 40 60 80 100 120 TEMPERATURE (C)
FIGURE 1. CHARGER OUTPUT VOLTAGE vs CHARGE CURRENT
FIGURE 2. CHARGER OUTPUT VOLTAGE vs TEMPERATURE
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ISL9203A Typical Operating Performance
The test conditions for the Typical Operating Performance are: VIN = 5V, TA = +25C, RIREF = RIMIN = 80k, VBAT = 3.7V, unless otherwise noted. (Continued)
2.0 4.30 1.8 CHARGE CURRENT = 50mA 4.25 VBAT (V) CHARGE CURRENT (A) 1.6 1.4 1.5A 1.2 1.0 0.8 0.6 0.4 0.2 4.10 4.2 4.5 4.8 5.1 5.4 VIN (V) 5.7 6 6.3 0.0 3.0 3.2 3.4 3.6 VVBAT (V) 3.8 4.0 0.5A 1A 2A
4.20
4.15
FIGURE 3. CHARGER OUTPUT VOLTAGE vs INPUT VOLTAGE CHARGE CURRENT IS 50mA
FIGURE 4. CHARGE CURRENT vs OUTPUT VOLTAGE
1.6 1.4 CHARGE CURRENT (A) 1.2 1.0 1.0A 0.8 0.6 0.4 0.2 0.0 0 20 40 60 80 100 120 TEMPERATURE (C) 0.5A 1.5A
2.0 1.8 CHARGE CURRENT (A) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 4.3 4.5 4.7 4.9 5.1 5.3 5.5 5.7 5.9 6.1 6.3 6.5 VIN (V) 0.5A 1A 1.5A
FIGURE 5. CHARGE CURRENT vs AMBIENT TEMPERATURE
FIGURE 6. CHARGE CURRENT vs INPUT VOLTAGE
2.930
3.00 2.95
2.928
V2P8 VOLTAGE (V)
V2P8 PIN LOADED WITH 2mA V2P8 VOLTAGE (V) 4.0 4.5 5.0 VIN (V) 5.5 6.0 6.5 2.90 2.85
2.926
2.924
2.80
2.922
2.75 2.920 3.5
2.70 0 2 4 6 8 10 V2P8 LOAD CURRENT (mA)
FIGURE 7. V2P8 OUTPUT vs INPUT VOLTAGE
FIGURE 8. V2P8 OUTPUT vs ITS LOAD CURRENT
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ISL9203A Typical Operating Performance
The test conditions for the Typical Operating Performance are: VIN = 5V, TA = +25C, RIREF = RIMIN = 80k, VBAT = 3.7V, unless otherwise noted. (Continued)
700 650 600 rDS(ON) (m) 550 500 450 400 350 300 250 200 0 20 40 60 80 100 120 TEMPERATURE (C) 280 260 3.0 3.2 3.4 3.6 VBAT (V) 3.8 4.0 THERMAL FOLDBACK STARTS NEAR +100C rDS(ON) (m) 420 400 380 360 340 320 300 500mA CHARGE CURRENT, RIREF = 40k
FIGURE 9. rDS(ON) vs TEMPERATURE AT 3.7V OUTPUT
FIGURE 10. rDS(ON) vs OUTPUT VOLTAGE USING CURRENT LIMITED ADAPTERS
1.8 VBAT LEAKAGE CURRENT (A) VIN QUIESCENT CURRENT (A) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0 20 40 60 80 100 120
50 45 40 35 30 25 20 15 10 5 0 TEMPERATURE (C) 0 20 40 60 80 100 120 EN = GND
TEMPERATURE (C)
FIGURE 11. REVERSE CURRENT vs TEMPERATURE
FIGURE 12. INPUT QUIESCENT CURRENT vs TEMPERATURE
32 30 VIN QUIESCENT CURRENT (A) 28 26 24 22 20 18 16 14 12 10 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 EN = GND VIN QUIESCENT CURRENT (mA)
1.10 1.05 1.00 0.95 0.90 0.85 0.80 4.3 BOTH VBAT AND EN PINS FLOATING
4.6
4.9
5.2
5.5 VIN (V)
5.8
6.1
6.4
VIN (V)
FIGURE 13. INPUT QUIESCENT CURRENT vs INPUT VOLTAGE WHEN SHUTDOWN
FIGURE 14. INPUT QUIESCENT CURRENT vs INPUT VOLTAGE WHEN NOT SHUTDOWN
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ISL9203A Typical Operating Performance
The test conditions for the Typical Operating Performance are: VIN = 5V, TA = +25C, RIREF = RIMIN = 80k, VBAT = 3.7V, unless otherwise noted. (Continued)
28 24 STATUS PIN CURRENT (mA) 20 16 12 8 4 0 0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
STATUS PIN VOLTAGE (V)
FIGURE 15. STATUS PIN VOLTAGE vs CURRENT WHEN THE OPEN-DRAIN MOSFET TURNS ON
Pin Descriptions
VIN (Pin1)
VIN is the input power source. Connect to a wall adapter.
EN (Pin 6)
EN is the enable logic input. Connect the EN pin to LOW to disable the charger or leave it floating to enable the charger.
NC (Pin 2)
No connection for this pin.
V2P8 (Pin 7)
This is a 2.8V reference voltage output. This pin outputs a 2.8V voltage source when the input voltage is above POR threshold, otherwise it outputs zero. The V2P8 pin can be used as an indication for adapter presence.
STATUS (Pin 3)
STATUS is an open-drain output indicating charging and inhibit states. The STATUS pin is pulled LOW when the charger is charging a battery. It will be forced to high impedence when the charge current drops to IMIN. This high impedence mode will be latched until a recharge cycle or a new charge cycle starts.
IREF (Pin 8)
This is the programming input for the constant charging current. It maintains at 0.8V when the charger is in normal operation.
TIME (Pin 4)
The TIME pin determines the oscillation period by connecting a timing capacitor between this pin and GND. The oscillator also provides a time reference for the charger.
VSEN (Pin 9)
VSEN is the remote voltage sense pin. Connect this pin as close as possible to the battery pack positive connection. If the VSEN pin is floating, its voltage drops to zero volt and the charger operates in the trickle mode.
GND (Pin 5)
GND is the connection to system ground.
VBAT (Pin 10)
VBAT is the connection to the battery. Typically a 10F Tantalum capacitor is needed for stability when there is no battery attached. When a battery is attached, only a 0.1F ceramic capacitor is required.
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ISL9203A Typical Applications
5V WALL ADAPTER VIN C1 10F R1 1 VBAT C2 10F ISL9203A BATTERY PACK
R2 1k
D1 VSEN STATUS V2P8 EN TIME CTIME 1nF IREF GND RIREF 80k C3 1F
Block Diagram
V IN
Q M A IN
VBAT
C1 REFERENCES TEM PERATURE M O N IT O R IN G R1 IT IS E N IN P U T _ O K + IR E F IR R IR E F CURRENT REFERENCES I M IN = I R /1 0 + CA CHRG + VA V CH + T R IC K L E /F A S T M IN B A T IS E N V M IN V POR Q SEN VMIN VRECHRG 1 0 0 0 0 0 :1 CURRENT M IR R O R VPOR VCH V 2P 8
V IN
VSEN
+ -
+
100m V
-
+ M IN _ I + RECHARGE IN P U T _ O K
V RECHRG
L O G IC
V IN EN E S D D IO D E STATUS STATUS T IM E GND OSC CO UNTER
FIGURE 16. BLOCK DIAGRAM
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ISL9203A Charging Flow Chart
POWER UP
VIN >VPOR ?
N
Y
POR
INITIALIZATION RESET STATUS RESET COUNTER
CC CHARGE TRICKLE CHARGE
CV CHARGE
VSEN> =V CH?
Y
VSEN>VMIN
ICH < IMIN ? Y
Y
N N
N
CONSTANT CURRENT CHARGE CONSTANT VOLTAGE CHARGE
TRICKLE CHARGE
EOC INDICATION: SET STATUS N HIGH
Y
VSEN < VRECHRG?
N
EN TOGGLED ?
N
Y
EOC
FIGURE 17. CHARGING STATE DIAGRAM
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ISL9203A Theory of Operation
The ISL9203A is an integrated charger for single-cell Li-ion or Li-polymer batteries. The ISL9203A functions as a traditional linear charger when powered with a voltagesource adapter. When powered with a current-limited adapter, the charger minimizes the thermal dissipation commonly seen in traditional linear chargers. As a linear charger, the ISL9203A charges a battery in the popular constant current (CC) and constant voltage (CV) profile. The constant charge current IREF is programmable up to 1.5A with an external resistor. The charge voltage VCH has 1% accuracy over the entire recommended operating condition range. The charger always preconditions the battery with 10% of the programmed current at the beginning of a charge cycle, until the battery voltage is verified to be above the minimum fast charge voltage, VMIN. This lowcurrent preconditioning charge mode is named trickle mode. The verification takes 15 cycles of an internal oscillator whose period is programmable with the timing capacitor. A thermal-foldback feature removes the thermal concern typically seen in linear chargers. The charger reduces the charge current automatically as the IC internal temperature rises above +100C to prevent further temperature rise. The thermal-foldback feature guarantees safe operation when the printed circuit board (PCB) is space limited for thermal dissipation. Two indication pins are available from the charger to indicate the charge status. The V2P8 outputs a 2.8V DC voltage when the input voltage is above the power-on reset (POR) level and can be used as a power-present indication. This pin is capable of sourcing a 2mA current, so it can also be used to bias external circuits. The STATUS pin is an opendrain logic output that goes LOW at the beginning of a charge cycle and stays LOW until the end-of-charge (EOC) condition is qualified. The EOC condition is met when the battery voltage rises above a recharge threshold and the charge current falls below an EOC current threshold. Once the EOC condition is qualified, the STATUS output goes HIGH and is latched. The latch is released at the beginning of a re-charge cycle, when the EN is toggled, or after the chip is power cycled. If the ISL9203A has not been power cycled and has not had the EN pin toggled, but the VSEN voltage drops below the recharge level, then the device re-enters the charge mode. In this condition, the charger indicates a re-charge cycle by bringing the STATUS pin LOW. When the wall adapter is not present, the ISL9203A draws less than 1A of current from the battery. Figure 18 shows the typical charge curves in a traditional linear charger powered with a constant-voltage adapter. From the top to bottom, the curves represent the constant input voltage, the battery voltage, the charge current and the power dissipation in the charger. The power dissipation PCH is given by the following equation:
P CH = ( V IN - V BAT ) I CHARGE (EQ. 1)
where ICHARGE is the charge current. The maximum power dissipation occurs during the beginning of the CC mode. The maximum power the IC is capable of dissipating is dependent on the thermal impedance of the printed-circuit board (PCB). Figure 18 shows, with dotted lines, two cases that the charge currents are limited by the maximum power dissipation capability due to the thermal foldback. When using a current-limited adapter, the thermal situation in the ISL9203A is totally different. Figure 19 shows the typical charge curves when a current-limited adapter is employed. The operation requires the IREF to be programmed higher than the limited current ILIM of the adapter, as shown in Figure 19. The key difference of the charger operating under such conditions occurs during the CC mode.
TRICKLE MODE CONSTANT CURRENT MODE CONSTANT VOLTAGE MODE INHIBIT
VIN INPUT VOLTAGE VCH BATTERY VOLTAGE
VMIN
IREF
CHARGE CURRENT
IREF/10 P1 P2 P3 POWER DISSIPATION
FIGURE 18. TYPICAL CHARGE CURVES USING A CONSTANT-VOLTAGE ADAPTER
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ISL9203A
The Block Diagram, Figure 16, aids in understanding the operation. The current loop consists of the current amplifier CA and the sense MOSFET QSEN. The current reference IR is programmed by the IREF pin. The current amplifier CA regulates the gate of the sense MOSFET QSEN so that the sensed current ISEN matches the reference current IR. The main MOSFET QMAIN and the sense MOSFET QSEN form a current mirror with a ratio of 100,000:1, that is, the output charge current is 100,000 times IR. In the CC mode, the current loop tries to increase the charge current by enhancing the sense MOSFET QSEN, so that the sensed current matches the reference current. On the other hand, the adapter current is limited, the actual output current will never meet what is required by the current reference. As a result, the current error amplifier CA keeps enhancing the QSEN as well as the main MOSFET QMAIN, until they are fully turned on. Therefore, the main MOSFET becomes a power switch instead of a linear regulation device. The power dissipation in the CC mode becomes:
P CH = r DS ( ON ) I CHARGE
2
ISL9203A. See the Application Information section of the ISL6292 data sheet (www.intersil.com) for more information. Figure 20 illustrates the typical signal waveforms for the linear charger from the power-up to a recharge cycle. More detailed Applications Information is given below.
Applications Information
Power on Reset (POR)
The ISL9203A resets itself as the input voltage rises above the POR rising threshold. The V2P8-pin outputs a 2.8V voltage, the internal oscillator starts to oscillate, the internal timer is reset, and the charger begins to charge the battery. The STATUS pin indicates a LOW logic signal. Figure 20 illustrates the start up of the charger between t0 to t2. The ISL9203A has a typical rising POR threshold of 3.4V and a falling POR threshold of 2.4V. The 2.4V falling threshold guarantees charger operation with a currentlimited adapter to minimize the thermal dissipation.
(EQ. 2)
Charge Cycle
A charge cycle consists of three charge modes: trickle mode, constant current (CC) mode, and constant voltage (CV) mode. The charge cycle always starts with the trickle mode until the battery voltage stays above VMIN (2.3V typical) for 15 consecutive cycles of the internal oscillator. If the battery voltage drops below VMIN during the 15 cycles, the 15-cycle counter is reset and the charger stays in the trickle mode. The charger moves to the CC mode after verifying the battery voltage is above VMIN. When the battery-pack terminal voltage rises to the final charge voltage VCH, the CV mode begins. The terminal voltage is regulated at the constant VCH in the CV mode and the charge current declines. After the charge current drops below IMIN (1/10 of IREF, see Section ""End-of-Charge (EOC) Current" on page 11 for more detail) the ISL9203A indicates the end-of-charge with the STATUS pin. The charging operation does not terminate. Signals in a charge cycle are illustrated in Figure 20 between points t2 to t5. The end of charge indicator (STATUS) will not be set if the charging current is below IMIN within the first 16 cycles after VBAT exceeds the VRECHRG voltage. If the charge current is still below IMIN after these 16 cycles, STATUS goes high to indicate end of charge. The following events initiate a new charge cycle: * POR, * the battery voltage drops below a recharge threshold,
where rDS(ON) is the resistance when the main MOSFET is fully turned on. This power is typically much less than the peak power in the traditional linear mode. The worst power dissipation when using a current-limited adapter typically occurs at the beginning of the CV mode, as shown in Figure 19. The equation 1 applies during the CV mode. When using a very small PCB whose thermal impedance is relatively large, it is possible that the internal temperature can still reach the thermal foldback threshold. In that case, the IC is thermally protected by lowering the charge current, as shown by the dotted lines in the charge current and power curves. Appropriate design of the adapter can further reduce the peak power dissipation of the
TRICKLE MODE
CONSTANT CURRENT MODE
CONSTANT VOLTAGE MODE
EOC
VIN VCH
INPUT VOLTAGE
BATTERY VOLTAGE
VMIN
IREF ILIM CHARGE CURRENT
IREF/10
P1 P2
POWER DISSIPATION
* or, the EN pin is toggled from GND to floating. Further description of these events are given later in this data sheet.
FIGURE 19. TYPICAL CHARGE CURVES USING A CURRENT LIMITED ADAPTER
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ISL9203A
Recharge
After a charge cycle completes, the charger continues to regulate the output at the constant voltage; but the STATUS pin indicates that the charging is completed. The STATUS pin stays high until the battery voltage drops to below the recharge threshold, VRECHRG (see Electrical Specifications). Then the STATUS pin goes low and a new charge cycle starts at point t6. The charge cycle ends at point t7 with the STATUS pin again going high, as shown in Figure 20.
TABLE 1. CHARGE CURRENT vs RIREF VALUES CHARGE CURRENT (mA) RIREF (k) 267 ~ 160 160 100 88.9 80
VIN POR THRESHOLD V2P8
MIN 17% lower than TYP Value 450 720 810 900
TYP = IREF in EQ. 5 500 800 900 1000
MAX 17% higher than TYP Value 550 880 990 1100
TABLE 2. TRICKLE CHARGE CURRENT vs RIREF VALUES
CHARGE CYCLE CHARGE CYCLE
TRICKLE CHARGE CURRENT (mA) RIREF (k) 267 MIN 15 30 40 45 70 TYP 30 50 80 90 100 MAX 60 80 120 135 150
STATUS
AT LEAST 15 CYCLES VBAT VRECHRG 2.8V V MIN IMIN t0 t1 t2 t3 t4 t5 t6 t7
160 100 88.9 80
ICHARGE
NOTE: The values in table 2 and table 1 are not tested and are only for guidance in selecting resistor values for mass production tests or in customer's products.
FIGURE 20. OPERATION WAVEFORMS
End-of-Charge (EOC) Current
The EOC current IMIN sets the level at which the charger starts to indicate the end of the charge with the STATUS pin, as shown in Figure 20. The charger actually does not terminate charging. In the ISL9203A, the EOC current is internally set to 1/10 of the CC charge current, that is:
1 I MIN = ----- I REF 10 (EQ. 5)
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:
T OSC = 0.2 10 C TIME
6
( sec onds )
(EQ. 3)
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.
At the EOC, the STATUS signal rises to HIGH and is latched. The latch is not reset until a recharge cycle or a new charge cycle starts. The tolerance guidance for the EOC current at selected RIREF values are given in Table 3.
TABLE 3. EOC CURRENT vs RIREF VALUES EOC CURRENT (mA) RIREF (k) 267 160 100 88.9 80 MIN 15 30 40 45 70 TYP 30 50 80 90 100 MAX 60 80 120 135 150
Charge Current Programming
The charge current in the CC mode is programmed by the IREF pin. The voltage of IREF is regulated to a 0.8V reference voltage. The charging current during the constant current mode is 100,000 times that of the current in the RIREF resistor. Hence, the charge current is,
5 0.8V I REF = ---------------- x 10 ( A ) R IREF
(EQ. 4)
Table 1 shows the charge current vs. selected RIREF values. The typical trickle charge current is 10% of the programmed constant charge current. Table 2 shows the trickle charge current tolerance guidance at given RIREF values, when the battery voltage is between 0V to 2.5V.
NOTE: The values in table 3 are not tested and are only for guidance in selecting resistor values for mass production tests or in customer's products.
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ISL9203A
IR
3.4V
IT
2.4V
I SEN
VIN
2.8V
+100C TEMPERATURE
FIGURE 21. CURRENT SIGNALS AT THE AMPLIFIER CA INPUT
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 ISL9203A frees users from the over-heating concern. Figure 21 shows the current signals at the summing node of the current error amplifier CA in the Block Diagram. IR is the reference. IT is the current from the Temperature Monitoring block. The IT has no impact on the charge current until the internal temperature reaches approximately +100C; then IT rises at a rate of 1A/C. When IT rises, the current control loop forces the sensed current ISEN to reduce at the same rate. As a mirrored 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 +110C. The actual charge current settles between +100C to +110C. 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.
FIGURE 22. THE V2P8 PIN OUTPUT vs THE INPUT VOLTAGE AT THE VIN PIN. VERTICAL: 1V/DIV, HORIZONTAL: 100ms/DIV
STATUS Pull-Up Resistor
The STATUS pin is an open-drain output that need an external pull-up resistor. It is recommended that this be pulled up to the input voltage or the 2.8V from the V2P8 pin. If the STSTUS pin has to be pulled up to other voltages, the user needs to examine carefully whether or not the ESD diodes will form a leakage current path to the battery when the input power is removed. If the leakage path does exist, an external transistor is required to break the path. Figure 23 shows the implementation. If the STATUS pin is directly pulled up to the VCC voltage (not shown in Figure 23), a current will flow from the VCC to the STATUS pin, then through the ESD diode to the VIN pin. Any leakage on the VIN pin, caused by an external or internal current path, will result in a current path from VCC to ground. The N-Channel MOSFET Q1 buffers the STATUS pin. The gate of Q1 is connected to VIN or the V2P8 pin. When the STATUS pin outputs a logic low signal, Q1 is turned on and its drain outputs a low signal as well. When STATUS is high impedance, R1 pulls the Q1 drain to high. When the input power is removed, the Q1 gate voltage is also removed, thus the Q1 drain stays high.
2.8V Bias Voltage
The ISL9203A 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.
Shutdown
The ISL9203A can be shutdown by pulling the EN pin to ground. When shut down, the charger draws typically less than 30A current from the input power and the 2.8V output at the V2P8 pin is also turned off. The EN pin needs be driven with an open-drain or open-collector logic output, so that the EN pin is floating when the charger is enabled. If the EN pin is driven by an external source, the POR threshold voltage will be affected.
Indications
The ISL9203A has two indications: the input presence and the charge status. The input presence is indicated by the V2P8 pin and the charge status is indicated by the STATUS pin. Figure 22 shows the V2P8 pin voltage vs. the input voltage.
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FN6430.0 February 14, 2007
ISL9203A
Board Layout Recommendations
VIN VCC
EN
RLKG
VIN or V2P8
CONTROL
R1
Q1 ESD DIODE STATUS
GND
Note: RLKG is approximately 240k when EN is floating and is approximately 140k when the EN is grounded. FIGURE 23. PULL-UP CIRCUIT TO AVOID BATTERY LEAKAGE CURRENT IN THE ESD DIODES
The ISL9203A internal thermal foldback function limits the charge current when the internal temperature reaches approximately +100C. 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 3x3 DFN package allows 8 vias be placed in two rows. Since the pins on the 3x3 DFN package are on only two sides, as much top layer copper as possible should be connected to the exposed pad to minimize the thermal impedance. Refer to the ISL6292 evaluation boards for layout examples.
Input and Output Capacitor Selection
Due to the inductance of the power leads of the wall adapter or USB source, the input capacitor type must be properly selected to prevent high voltage transient during a hot-plug event. A tantalum capacitor is a good choice for its high ESR, providing damping to the voltage transient. Multi-layer ceramic capacitors, however, have a very low ESR and hence when chosen as input capacitor, a 1 series resistor must be used, as shown in the Typical Applications Section, to provide adequate damping. The output capacitor can be any ceramic type with the value higher than 0.1F. However, if there is a chance the charger will be used as an LDO linear regulator, a 10F tantalum capacitor is recommended. Note that the charger always steps through the 15-cycle VMIN verification time before the charge current rises to the constant charge current, as discussed earlier. Hence, when using as an LDO, the system should make sure not to load the charger heavily until the 15-cycle verification is completed.
Working with Current-Limited Adapter
The ISL9203A can work with a current-limited adapter to significantly reduce the thermal dissipation during charging. Refer to the ISL6292 data sheet, which can be found at http://www.intersil.com, for more details.
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FN6430.0 February 14, 2007
ISL9203A Dual Flat No-Lead Plastic Package (DFN)
2X 0.15 C A A D 2X 0.15 C B
L10.3x3
10 LEAD DUAL FLAT NO-LEAD PLASTIC PACKAGE MILLIMETERS SYMBOL A A1 MIN 0.80 0.18 1.95 1.55 0.25 0.30 NOMINAL 0.90 0.20 REF 0.23 3.00 BSC 2.00 3.00 BSC 1.60 0.50 BSC 0.35 10 5 0.40 1.65 2.05 0.28 MAX 1.00 0.05 NOTES 5,8 7,8 7,8 8 2 3 Rev. 3 6/04 NOTES: 1. Dimensioning and tolerancing conform to ASME Y14.5-1994. 2. N is the number of terminals. 3. Nd refers to the number of terminals on D. 4. All dimensions are in millimeters. Angles are in degrees. 5. Dimension b applies to the metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 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. 7. Dimensions D2 and E2 are for the exposed pads which provide improved electrical and thermal performance. 8. Nominal dimensions are provided to assist with PCB Land Pattern Design efforts, see Intersil Technical Brief TB389.
E 6 INDEX AREA TOP VIEW B
A3 b D D2 E E2
0.10 C
e k L N Nd
A 0.08 C C SEATING PLANE SIDE VIEW A3
7 (DATUM B) 6 INDEX AREA (DATUM A) 1 2 D2
8
D2/2 NX k E2 E2/2
NX L N 8 N-1 NX b e (Nd-1)Xe REF. BOTTOM VIEW 5 0.10 M C A B
C L 0.415 NX (b) 5 SECTION "C-C" C NX b (A1) 0.200 L NX L e CC TERMINAL TIP
FOR ODD TERMINAL/SIDE
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation's quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com 14
FN6430.0 February 14, 2007

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