Renesas ISL88731C Datasheet
DATASHEET
CHARGE TIME (MINUTES)
10.0
10.5
11. 0
11. 5
12.0
12.5
13.0
0 20 40 60 80 100 120 140 160
BATTERY VOLTAGE
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
BATTERY CURRENT
VCHG (V)
ICHG (A)
80
85
90
95
100
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
I
OUT
(A)
EFFICIENCY (%)
8.4V BATTERY
12.6V BATTERY
16.8V BATTERY
4.2V BATTERY
ISL88731C
SMBus Level 2 Battery Charger
The ISL88731C is a highly integrated Lithium-ion battery
charger controller, programmable over the SMBus system
management bus (SMBus). The ISL88731C is intended to be
used in a smart battery charger (SBC) within a smart battery
system (SBS) that throttles the charge power such that the
current from the AC-adapter is automatically limited. High
efficiency is achieved with a DC/DC synchronous-rectifier buck
converter, equipped with diode emulation for enhanced light
load efficiency and system bus boosting prevention. The
ISL88731C charges one to four Lithium-ion series cells, and
delivers up to 8A charge current. Integrated MOSFET drivers
and bootstrap diode result in fewer components and smaller
implementation area. Low offset current-sense amplifiers
provide high accuracy with 10m sense resistors. The
ISL88731C provides 0.5% end-of-charge battery voltage
accuracy.
The ISL88731C provides a digital output that indicates the
presence of the AC adapter as well as an analog output which
indicates the adapter current within 4% accuracy.
The ISL88731C is available in a small 5mmx5mm 28 Ld Thin
(0.8mm) QFN package. An evaluation kit is available to reduce
design time. The ISL88731C is available in Pb-Free packages.
FN6978
Rev 3.00
June 8, 2011
Features
• 0.5% Battery Voltage Accuracy
• 3% Adapter Current Limit Accuracy
• 3% Charge Current Accuracy
• SMBus 2-Wire Serial Interface
• Battery Short Circuit Protection
• Fast Response for Pulse-Charging
• Fast System-Load Transient Response
• Monitor Outputs
- Adapter Current (3% Accuracy)
- AC-Adapter Detection
• 11-Bit Battery Voltage Setting
• 6 Bit Charge Current/Adapter Current Setting
• 8A Maximum Battery Charger Current
• 11A Maximum Adapter Current
• +8V to +26V Adapter Voltage Range
• Pb-Free (RoHS Compliant)
Related Literature
•See AN1404 for “ISL88731EVAL2Z and ISL88731CEVAL2Z
Evaluation Boards Setup Procedure”
FIGURE 1. TYPICAL CHARGING VOLTAGE AND CURRENT
FN6978 Rev 3.00 Page 1 of 26
June 8, 2011
Applications
• Notebook Computers
•Tablet PCs
• Portable Equipment with Rechargeable Batteries
FIGURE 2. EFFICIENCY vs CHARGE CURRENT AND BATTERY
VOLTAGE
ISL88731C
FIGURE 3. FUNCTIONAL BLOCK DIAGRAM
SMBUS
VDDSMB
DC/DC
CONVERTER
SDA
VFB
CSOP
PHASE
LGATE
UGATE
BOOT
PGND
VDDP
LVB
SCL
+
-
GMV
+
-
GMI
DACI
DACS
DACV
+
-
GMS
LEVEL
SHIFTER
20x
LEVEL
SHIFTER
20x
CSON
CSSP
CSSN
ICOMP
VCOMP
VCC
11
6
6
DACS
DACI
DACV
DACS
DACI
DACV
LVB
REFERENCE
LINEAR
REGULATOR
DCIN
VREF
+
-
ACIN
ACOK
3.2V
BUFF
ICM
CSSP
EN
CSO
EN
GND
EN
VDDP
100k
500k
PHASE
BOOT
UGATE
LGATE
PGND
ISL88731C
CSSNCSSP
CSOP
CSON
ACIN
SCL
VREF
DCIN
SDA
VDDSMB
ICM
ICOMP
VCOMP
VCC
ACOK
VDDP
GND
AC ADAPTER
TO BATTERY
TO SYSTEM
HOST
VFB
RS1
RS2
AGND
PGND
AGND
FIGURE 4. TYPICAL APPLICATION CIRCUIT
FN6978 Rev 3.00 Page 2 of 26
June 8, 2011
ISL88731C
CSSP
CSSN
VCC
BOOT
UGATE
PHASE
DCIN
ICM
SDA
SCL
VDDSMB
GND
ACOK
NC
NC
ACIN
VREF
ICOMP
NC
VCOMP
NC
VDDP
LGATE
PGND
CSOP
CSON
NC
VFB
1
2
3
4
5
6
7
21
20
19
18
17
16
15
28 27 26 25 24 23 22
8 9 10 11 12 13 14
PD
Pin Configuration
ISL88731C
(28 LD TQFN)
TOP VIEW
Functional Pin Descriptions
PIN NUMBER SYMBOL DESCRIPTION
2 ACIN AC Adapter Detection Input. Connect to a resistor divider from the AC adapter output. Range zero to 5.5V.
3 VREF Reference Voltage output. Range 3.168V to 3.232V. It is internally compensated. Do not connect a decoupling capacitor.
4 ICOMP Compensation Point for the charging current and adapter current regulation Loop. Connect 0.01µF to GND. See
6 VCOMP Compensation Point for the voltage regulation loop. Connect 4.7k in series with 0.01µF to GND. See “Voltage Control
8 ICM Input Current Monitor Output. ICM voltage equals 20 x (V
9 SDA SMBus Data I/O. Open-drain Output. Connect an external pull-up resistor according to SMBus specifications. Range
10 SCL SMBus Clock Input. Connect an external pull-up resistor according to SMBus specifications. Range zero to 5.5V.
11 VDDSMB SMBus interface Supply Voltage Input. Bypass with a 0.1µF capacitor to GND. Range 3.3V to 5.5V.
12 GND Analog Ground. Connect directly to the backside paddle. Connect to the backside paddle and PGND at one point close
13 ACOK AC Detect Output. This open drain output is high impedance when ACIN is greater than 3.2V. The ACOK output remains low
15 VFB Feedback for the Battery Voltage. Range 1V to 19V.
17 CSON Charge Current-Sense Negative Input. Range 1V to 19V.
18 CSOP Charge Current-Sense Positive Input. Range 1V to 19V.
19 PG ND Power Ground. Connect PGND to the source of the low side MOSFET and the negative side of capacitors to the charger output
20 LGATE Low-Side Power MOSFET Driver Output. Connect to low-side N channel MOSFET. LGATE drives between VDDP and
“Voltage Control Loop” on page 21 for details on selecting the ICOMP capacitor. Range zero to 5.5V.
Loop” on page 21 for details on selecting VCOMP components. Range zero to 5.5V.
zero to 5.5V.
to (under) the IC.
when the ISL88731C is powered down. Connect a 10k pull-up resistor from ACOK to VDDSMB. Range 3.3V to 5.5V.
and the drain of the upper switching FET. Connect this area to the Backside paddle at one location very near (under) the IC.
PGND. Range is -0.3V to 5.23V.
CSSP
- V
). Range zero to 3V.
CSSN
FN6978 Rev 3.00 Page 3 of 26
June 8, 2011
ISL88731C
Functional Pin Descriptions (Continued)
PIN NUMBER SYMBOL DESCRIPTION
21 VDDP Linear Regulator Output. VDDP is the output of the 5.2V linear regulator supplied from DCIN. VDDP also directly
supplies the LGATE driver and the BOOT strap diode. Bypass with a 1µF ceramic capacitor from VDDP to PGND. Range
is 5.0V to 5.23V.
22 DCIN Charger Bias Supply Input. Bypass DCIN with a 0.1µF capacitor to GND. Range 8V to +26V.
23 PHASE High-Side Power MOSFET Driver Source Connection. Connect to the source of the high-side N-Channel MOSFET. Range
-2V to +26V.
24 UGATE High-Side Power MOSFET Driver Output. Connect to the high-side N-channel MOSFET gate. Range -2V to +33V.
25 BOOT High-Side Power MOSFET Driver Power-Supply Connection. Connect a 0.1µF capacitor from BOOT-to-PHASE. Range
-2V to +33V.
26 VCC Power input for internal analog circuits. Connect a 4.7 resistor from VCC to VDDP and a 1µF ceramic capacitor from VCC
to ground. Range 4V to 5.23V.
27 CSSN Input Current-Sense Negative Input. Range 8V to 26V.
28 CSSP Input Current-Sense Positive Input. Range 8V to 26V.
PD Connect the backside paddle to GND. This pad has the lowest thermal resistance to the die. It should be connected to
a large area of ground with 3 to 5 vias for good thermal performance. The recommended potential of the thermal pad
is zero (0) Volts.
1, 5, 7, 14, 16 NC No Connect. Pins are not connected internally.
Ordering Information
PART NU MBER
(Notes 1, 2, 3)
ISL88731CHRTZ 88731C HRTZ -10 to +100 28 Ld 5x5 TQFN L28.5x5B
ISL88731CEVAL2Z Evaluation Board
NOTES:
1. Add “-T*” suffix for tape and reel. Please refer to TB347
2. These Intersil 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). 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.
3. For Moisture Sensitivity Level (MSL), please see device information page for ISL88731C
PART
MARKING
TEMP RANGE
(°C)
for details on reel specifications.
PACKAGE
(Pb-Free)
. For more information on MSL please see tech brief TB363.
PKG.
DWG. #
FN6978 Rev 3.00 Page 4 of 26
June 8, 2011
ISL88731C
Table of Contents
Absolute Maximum Ratings ...................................................6
Thermal Information ...............................................................6
Electrical Specifications ........................................................6
SMBus Timing Specifications.................................................8
Typical Operating Performance................................................... 9
Theory of Operation ............................................................. 11
Introduction ..................................................................................11
PWM Control................................................................................. 11
AC-Adapter Detection.................................................................. 11
Current Measurement.................................................................11
VDDP Regulator ...........................................................................11
VDDSMB Supply........................................................................... 11
Short Circuit Protection and 0V Battery Charging ..................11
Undervoltage Detect and Battery Trickle Charging ................11
Over-Temperature Protection ....................................................12
Overvoltage Protection ...............................................................12
The System Management Bus................................................... 12
General SMBus Architecture......................................................12
Data Validity .................................................................................12
START and STOP Conditions.............................................................. 12
Acknowledge......................................................................................... 13
SMBus Transactions............................................................................13
Byte Format .......................................................................... 13
Power and Signal Layers Placement on the PCB ................... 22
Component Placement............................................................... 22
Signal Ground and Power Ground Connection........................ 22
GND and VCC Pin......................................................................... 22
LGATE Pin ..................................................................................... 22
PGND Pin ...................................................................................... 22
PHASE Pin .................................................................................... 23
UGATE Pin..................................................................................... 23
BOOT Pin....................................................................................... 23
CSOP, CSON, CSSP and CSSN Pins ..........................................23
DCIN Pin........................................................................................ 23
Copper Size for the Phase Node ............................................... 23
Identify the Power and Signal Ground ..................................... 23
Clamping Capacitor for Switching MOSFET............................. 23
Revision History ................................................................... 24
Products................................................................................ 24
Package Outline Drawing .................................................... 25
ISL88731C and SMBus ......................................................... 13
Battery Charger Registers................................................... 14
Enabling and Disabling Charging........................................ 14
Setting Charge Voltage........................................................ 14
Setting Charge Current ........................................................ 15
Setting Input-Current Limit.................................................. 16
Charger Timeout ....................................................................17
ISL88731C Data Byte Order..................................................17
Writing to the Internal Registers .........................................17
Reading from the Internal Registers...................................17
Application Information .......................................................17
Inductor Selection........................................................................17
Output Capacitor Selection ........................................................18
MOSFET Selection........................................................................ 18
Snubber Design............................................................................19
Input Capacitor Selection ...........................................................19
Loop Compensation Design .......................................................19
Transconductance Amplifiers GMV, GMI and GMS.................19
PWM Gain Fm ..............................................................................19
Charge Current Control Loop .....................................................20
Adapter Current Limit Control Loop .......................................... 20
Voltage Control Loop...................................................................21
Output LC Filter Transfer Functions ..........................................21
Compensation Break Frequency Equations ............................22
PCB Layout Considerations................................................. 22
FN6978 Rev 3.00 Page 5 of 26
June 8, 2011
ISL88731C
Absolute Maximum Ratings Thermal Information
DCIN, CSSP, CSSN, CSOP, CSON, VFB . . . . . . . . . . . . . . . . . . . -0.3V to +28V
CSSP-CSSN, CSOP-CSON, PGND-GND . . . . . . . . . . . . . . . . . . -0.3V to +0.3V
PHASE to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -6V to +30V
BOOT to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +33V
BOOT to PHASE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6V
UGATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PHASE - 0.3V to BOOT + 0.3V
LGATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PGND - 0.3V to VDDP + 0.3V
ICOMP, VCOMP, VREF, to GND. . . . . . . . . . . . . . . . . . . . . -0.3V to VCC + 0.3V
VDDSMB, SCL, SDA, ACIN, ACOK . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6V
VDDP, ICM, VCC to GND, VDDP to PGND . . . . . . . . . . . . . . . . . . -0.3V to +6V
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product
reliability and result in failures not covered by warranty.
NOTES:
4.
is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech
JA
Brief TB379.
5. For
, the “case temp” location is the center of the exposed metal pad on the package underside.
JC
Thermal Resistance (Typical) JA (°C/W) JC (°C/W)
28 Ld TQFN Package (Notes 4, 5) . . . . . . . 38 6.5
Junction Temperature Range . . . . . . . . . . . . . . . . . . . . . . . -55C to +150°C
Operating Temperature Range . . . . . . . . . . . . . . . . . . . . . . -10C to +100°C
Storage Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -65C to +150°C
Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Electrical Specifications DCIN = CSSP = CSSN = 18V, CSOP = CSON = 12V, VDDP = 5V, BOOT-PHASE = 5.0V, GND = PGND = 0V,
CVDDP = 1µF, IVDDP = 0mA, T
PARAMETER CONDITIONS
CHARGE VOLTAGE REGULATION
Battery Full Charge Voltage and Accuracy ChargeVoltage = 0x41A0 16.716 16.8 16.884 V
Battery Undervoltage Lockout Trip Point for
Trick le Ch arge
Battery Undervoltage Lockout Trip Point
Hysteresis
CHARGE CURRENT REGULATION
CSOP to CSON Full-Scale
Current-Sense Voltage
Charge Current and Accuracy RS2 = 10m (see Figure 4)
Charge Current Gain Error Based on charge current = 128mA and 8.064A -1.6 1.4 %
CSOP/CSON Input Voltage Range 019V
= -10°C to +100°C. Boldface limits apply over the operating temperature range, -10°C to +100°C.
A
MIN
(Note 7) TYP
-0.5 0.5 %
ChargeVoltage = 0x3130 12.529 12.592 12.655 V
-0.5 0.5 %
ChargeVoltage = 0x20D0 8.350 8.4 8.450 V
-0.6 0.6 %
ChargeVoltage = 0x1060 4.163 4.192 4.221 V
-0.7 0.7 %
VFB rising 2.55 2.7 2.85 V
100 250 400 mV
78.22 80.64 83.06 mV
7.822 8.064 8.306 A
ChargingCurrent = 0x1f80
RS2 = 10m (see Figure 4)
ChargingCurrent = 0x0f80
RS2 = 10m (see Figure 4)
ChargingCurrent = 0x0080
-3 3 %
3.809 3.968 4.126 A
-4 4 %
64 128 220 mA
MAX
(Note 7) UNITS
FN6978 Rev 3.00 Page 6 of 26
June 8, 2011
ISL88731C
Electrical Specifications DCIN = CSSP = CSSN = 18V, CSOP = CSON = 12V, VDDP = 5V, BOOT-PHASE = 5.0V, GND = PGND = 0V,
CVDDP = 1µF, IVDDP = 0mA, T
PARAMETER CONDITIONS
Battery Quiescent Current Adapter present, not charging,
Adapter Quiescent Current I
INPUT CURRENT REGULATION
CSSP to CSSN Full-Scale Current-Sense
Voltage
Input Current Accuracy RS1 = 10m (see Figure 4)
Input Current Limit Gain Error Based on InputCurrent = 1024mA and 11004mA -1.5 1.5 %
Input Current Limit Offset -1 1 mV
CSSP/CSSN Input Voltage Range 826V
ICM Gain V
ICM Accuracy V
ICM Max Output Current V
SUPPLY AND LINEAR REGULATOR
DCIN, Input Voltage Range 826V
VDDP Output Voltage 8.0V < V
VDDP Load Regulation 0 < I
VDDSMB Range 2.7 5.5 V
VDDSMB UVLO Rising 2.4 2.5 2.6 V
VDDSMB UVLO Hysteresis 40 100 150 mV
VDDSMB Quiescent Current VDDP = SCL = SDA = 5.5V 20 27 µA
V REFERENCE
VREF Output Voltage 0 < I
ACOK
ACOK Sink Current V
ACOK Leakage Current V
ACIN
ACIN rising Threshold 3.15 3.2 3.25 V
ACIN Threshold Hysteresis 40 60 90 mV
ACIN Input Bias Current -1 1 µA
= -10°C to +100°C. Boldface limits apply over the operating temperature range, -10°C to +100°C. (Continued)
A
MIN
(Note 7) TYP
MAX
(Note 7) UNITS
135 200 µA
I
+ I
= V
= 5V
CSON
CSON
+ I
CSOP
V
PHASE
V
ACIN
Adapter Absent
I
+ I
+ I
CSON
= V
CSSP
+ I
CSON
+ I
CSOP
V
PHASE
DCIN
Vadapter = 8V to 26V, Vbattery 4V to 16.8V
PHASE
= V
PHASE
= V
CSSN
CSOP
CSOP
+ I
CSSP
= V
+ I
CSSP
= 19V, V
DCIN
+ I
CSSN
= 19V,
+ I
CSSN
DCIN
+ I
+ I
= 0V
FB
-1 0.2 2 µA
FB
3 5 mA
CSSP = 19V 106.7 110 113.3 mV
-3 3 %
Adapter Current = 11004mA or 3584mA
RS1 = 10m (see Figure 4)
-5 5 %
Adapter Current = 2048mA
CSSP-CSSN
CSSP-CSSN
V
CSSP-CSSN
V
CSSP-CSSN
CSSP-CSSN
ACOK
ACOK
= 110mV 20 V/V
= 110mV -2.5 2.5 %
= 55mV or 35mV -4 4 %
= 20mV -8 8 %
= 0.1V 500 µA
< 28V, no load 5.0 5.1 5.23 V
DCIN
< 30mA 35 100 mV
VDDP
< 300µA 3.168 3.2 3.232 V
VREF
= 0.4V, ACIN = 1.5V 2 8mA
= 5.5V, ACIN = 3.7V 1 µA
FN6978 Rev 3.00 Page 7 of 26
June 8, 2011
ISL88731C
Electrical Specifications DCIN = CSSP = CSSN = 18V, CSOP = CSON = 12V, VDDP = 5V, BOOT-PHASE = 5.0V, GND = PGND = 0V,
CVDDP = 1µF, IVDDP = 0mA, T
PARAMETER CONDITIONS
SWITCHING REGULATOR
Frequency 330 400 440 kHz
BOOT Supply Current UGATE High 170 290 400 µA
PHASE Input Bias Current V
UGATE On-Resistance Low I
UGATE On-Resistance High I
LGATE On-Resistance High I
LGATE On-Resistance Low I
Dead Time Falling UGATE to rising LGATE or
ERROR AMPLIFIERS
GMV Amplifier Transconductance 200 250 300 µA/V
GMI Amplifier Transconductance 40 50 60 µA/V
GMS Amplifier Transconductance 40 50 60 µA/V
GMI/GMS Saturation Current 15 21 25 µA
GMV Saturation Current 10 17 30 µA
ICOMP, VCOMP Clamp Voltage 0.25V < V
LOGIC LEVELS
SDA/SCL Input Low Voltage VDDSMB = 2.7V to 5.5V 0.8 V
SDA/SCL Input High Voltage VDDSMB = 2.7V to 5.5V 2 V
SDA/SCL Input Bias Current VDDSMB = 2.7V to 5.5V -1 1 µA
SDA, Output Sink Current V
= -10°C to +100°C. Boldface limits apply over the operating temperature range, -10°C to +100°C. (Continued)
A
MIN
(Note 7) TYP
= 28V, V
DCON
= -100mA 0.9 1.6
UGATE
= 10mA 1.4 2.5
UGATE
= +10mA 1.4 2.5
LGATE
= -100mA 0.9 1.6
LGATE
falling LGATE to rising UGATE
ICOMP, VCOMP
= 0.4V 7 15 mA
SDA
CSON
= V
= 20V 0 2 µA
PHASE
35 50 80 ns
< 3.5V 200 300 400 mV
MAX
(Note 7) UNITS
SMBus Timing Specifications VDDSMB = 2.7V to 5.5V.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SMBus Frequency FSMB 10 100 kHz
Bus Free Time t
Start Condition Hold Time from SCL t
Start Condition Setup Time from SCL t
Stop Condition Setup Time from SCL t
SDA Hold Time from SCL t
SDA Setup Time from SCL t
SCL Low Timeout (Note 6) t
SCL Low Period t
SCL High Period t
Maximum Charging Period without an SMBus Write to
ChargeVoltage or ChargeCurrent Register
NOTES:
6. If SCL is low for longer than the specified time, the charger is disabled.
7. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization
and are not production tested.
BUF
HD:STA
SU:STA
SU:STO
HD:DAT
SU:DAT
TIMEOUT
LOW
HIGH
FN6978 Rev 3.00 Page 8 of 26
June 8, 2011
4.7 µs
4µs
4.7 µs
4µs
300 ns
250 ns
22 25 30 ms
4.7 µs
4µs
140 180 220 s
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