MAX1647EAP+ ,Chemistry-Independent Battery ChargersApplicationsMAX1647EAP -40°C to +85°C 20 SSOPNotebook ComputersMAX1648ESE -40°C to +85°C 16 Narrow ..
MAX1648ESE ,Chemistry-Independent Battery ChargersELECTRICAL CHARACTERISTICS(V = 18V, V = 4.096V, T = 0°C to +85°C. Typical values are at T = +25°C, ..
MAX1649CPA ,5V/3.3V or Adjustable, High-Efficiency, Low-Dropout, Step-Down DC-DC ControllersELECTRICAL CHARACTERISTICS(V+ = 5V, T = T to T , unless otherwise noted. Typical values are at T = ..
MAX1649CSA ,5V/3.3V or Adjustable, High-Efficiency, Low-Dropout, Step-Down DC-DC ControllersFeaturesThe MAX1649/MAX1651 BiCMOS, step-down, DC-DC ' More than 90% Efficiency (10mA to 1.5A Loads ..
MAX1649CSA ,5V/3.3V or Adjustable, High-Efficiency, Low-Dropout, Step-Down DC-DC ControllersApplications MAX1651CPA 0°C to +70°C 8 Plastic DIPMAX1651CSA 0°C to +70°C 8 SOPDAsMAX1651C/D 0°C to ..
MAX1649CSA+ ,5V/3.3V or Adjustable, High-Efficiency, Low-Dropout, Step-Down DC-DC ControllerFeaturesThe MAX1649/MAX1651 BiCMOS, step-down, DC-DC ♦ More than 90% Efficiency (10mA to 1.5A Loads ..
MAX4400AUK-T ,Single/Dual/Quad / Low-Cost / Single-Supply / Rail-to-Rail Op Amps with ShutdownELECTRICAL CHARACTERISTICS (continued)(V = +5V, V = 0, V = 0, V = V /2, R = ∞ connected to V /2, SH ..
MAX4400AXK+T ,Single/Dual/Quad, Low-Cost, Single-Supply, Rail-to-Rail Op Amps with ShutdownElectrical Characteristics (continued)(V = +5V, V = 0V, V = 0V, V = V /2, R = ∞ connected to V /2, ..
MAX4400AXK-T ,Single/Dual/Quad / Low-Cost / Single-Supply / Rail-to-Rail Op Amps with ShutdownELECTRICAL CHARACTERISTICS(V = +5V, V = 0, V = 0, V = V /2, R = ∞ connected to V /2, SHDN = V (MAX4 ..
MAX4400AXK-T ,Single/Dual/Quad / Low-Cost / Single-Supply / Rail-to-Rail Op Amps with ShutdownApplications*Future product—contact factory for availability.Single-Supply Zero-Crossing DetectorsI ..
MAX4401AXT ,Single/Dual/Quad, Low-Cost, Single-Supply, Rail-to-Rail Op Amps with ShutdownElectrical Characteristics(V = +5V, V = 0V, V = 0V, V = V /2, R = ∞ connected to V /2, SHDN = V (MA ..
MAX4401AXT+T ,Single/Dual/Quad, Low-Cost, Single-Supply, Rail-to-Rail Op Amps with ShutdownFeaturesThe MAX4400–MAX4403 low-cost, general-purpose op ● Single +2.5V to +5.5V Supply Voltage Ran ..
MAX1647EAP+
Chemistry-Independent Battery Chargers
_______________General DescriptionThe MAX1647/MAX1648 provide the power control neces-
sary to charge batteries of any chemistry. In the MAX1647,
all charging functions are controlled through the Intel
System Management Bus (SMBus™) interface. The
SMBus 2-wire serial interface sets the charge voltage and
current, and provides thermal status information. The
MAX1647 functions as a level 2 charger, compliant with
the Duracell/Intel Smart Battery Charger Specification. The
MAX1648 omits the SMBus serial interface, and instead
sets the charge voltage and current proportional to the
voltage applied to external control pins.
In addition to the feature set required for a level 2 charger,
the MAX1647 generates interrupts to signal the host when
power is applied to the charger or a battery is installed or
removed. Additional status bits allow the host to check
whether the charger has enough input voltage, and
whether the voltage on or current into the battery is being
regulated. This allows the host to determine when lithium-
ion batteries have completed charge without interrogating
the battery.
The MAX1647 is available in a 20-pin SSOP with a 2mm
profile height. The MAX1648 is available in a 16-pin SO
package.
________________________ApplicationsNotebook Computers
Personal Digital Assistants
Charger Base Stations
Phones
____________________________FeaturesCharges Any Battery Chemistry:
Li-Ion, NiCd, NiMH, Lead Acid, etc.Intel SMBus 2-Wire Serial Interface (MAX1647)Intel/Duracell Level 2 Smart Battery Compliant
(MAX1647)4A, 2A, or 1A Maximum Battery-Charge Current11-Bit Control of Charge CurrentUp to 18V Battery Voltage10-Bit Control of Voltage±0.75% Voltage Accuracy with External ±0.1%
ReferenceUp to 28V Input VoltageBattery Thermistor Fail-Safe Protection
MAX1647/MAX1648
Chemistry-Independent Battery ChargersBST
DHI
DLOCCV
DCIN
IOUT
TOP VIEW
PGND
DACV
SDA
SCLBATT
SEL
CCI
THM
INTAGND
REF
MAX1647
SSOPBST
DHI
DLO
PGND
SETV
SETI
THM
DCIN
CCV
CCI
BATT
REF
AGND
MAX1648
__________________________________________________________Pin Configurations
PART
MAX1647EAP
MAX1648ESE-40°C to +85°C
-40°C to +85°C
TEMP RANGEPIN-PACKAGE20 SSOP
16 Narrow SO
______________Ordering InformationSMBus is a trademark of Intel Corp.
19-1158; Rev 1; 12/02
MAX1647/MAX1648
Chemistry-Independent Battery Chargers
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VDCIN= 18V, VREF= 4.096V, TA
= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
DCIN to AGND..........................................................-0.3V to 30V
DCIN to IOUT...........................................................-0.3V to 7.5V
BST to AGND............................................................-0.3V to 36V
BST, DHI to LX............................................................-0.3V to 6V
LX to AGND..............................................................-0.3V to 30V
THM, CCI, CCV, DACV, REF,
DLO to AGND................................................-0.3V to (VL + 0.3V)
VL, SEL, INT, SDA, SCL to AGND (MAX1647)...........-0.3V to 6V
SETV, SETI to AGND (MAX1648)................................-0.3V to 6V
BATT, CS+ to AGND.................................................-0.3V to 20V
PGND to AGND.....................................................-0.3V to +0.3V
SDA, INTCurrent................................................................50mA
VL Current...........................................................................50mA
Continuous Power Dissipation (TA= +70°C)
16-Pin SO (derate 8.7mW/°C above +70°C).................696mW
20-Pin SSOP (derate 8mW/°C above +70°C)...............640mW
Operating Temperature Range
MAX1647EAP, MAX1648ESE...........................-40°C to +85°C
Storage Temperature.........................................-60°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C-0.65+0.65
MAX1647, ChargingVoltage( ) = 0x1060,
ChargingVoltage( ) = 0x3130; MAX1648,
VSETV= 3.15V, VSETV= 1.05V
Voltage Accuracy2.94MAX1647, SEL = open,
ChargingCurrent( ) = 0x0020
CS to BATT Single-Count
Current-Sense Voltage019BATT, CS Input Voltage Range350500VL < 5.15V, VBATT= 12VBATT Input Current (Note 1)15VL < 3.2V, VBATT= 12V614High or lowDLO On-Resistance47High or lowDHI On-Resistance467.5V < VDCIN< 28V, logic inputs = VLDCIN Quiescent Current7.528.0DCIN Input Voltage Range8993DHI Maximum Duty Cycle
kHz200250300Oscillator Frequency700REF Overdrive Input Current5.155.45.657.5V < VDCIN< 28V, no loadVL Output Voltage100ILOAD= 10mAVL Load Regulation3.2045.15MAX1647VL AC_PRESENT Trip Point3.743.94.070µA < ISOURCE< 500µAREF Output Voltage
UNITSMINTYPMAXCONDITIONSPARAMETER170400VL < 5.15V, VCS= 12VCS Input Current (Note 1)15VL < 3.2V, VCS= 12V170185200
MAX1647, SEL = open,
ChargingCurrent( ) = 0x07F0;
MAX1648, VSETI= 1.024V
CS to BATT Full-Scale
Current-Sense Voltage
SUPPLY AND REFERENCE
SWITCHING REGULATOR
MAX1647/MAX1648
Chemistry-Independent Battery Chargers
ELECTRICAL CHARACTERISTICS (continued)(VDCIN= 18V, VREF= 4.096V, TA
= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.)
Note 1:When DCIN is less than 4V, VL is less than 3.2V, causing the battery current to be typically 2µA (CS plus BATT input
current).01.024SETI Input Voltage Range04.2SETV Input Voltage Range5SETI Input Bias Current1SETV Input Bias Current
Bits10Guaranteed monotonicVDAC Voltage-Setting DAC Resolution
Bits6Guaranteed monotonicCDAC Current-Setting DAC Resolution-7.5-1.0With respect to DCIN voltageIOUT Operating Voltage Range253138MAX1647,
VDCIN= 7.5V,
VIOUT= 0V
IOUT Output Current
% of
VREF34.56MAX1647THM THERMISTOR_UR
Under-Range Trip Point
% of
VREF2223.525THM THERMISTOR_HOT
Trip Point
% of
VREF7475.577THM THERMISTOR_COLD
Trip Point
mA/V0.2GMI Amplifier Transconductance
mA/V1.4GMV Amplifier Transconductance
% of
VREF89.59192.5MAX1647THM THERMISTOR_OR
Over-Range Trip Point
% of
VDCIN86.58991.5MAX1647BATT POWER_FAIL Trip Point±80GMV Amplifier Maximum
Output Current±200GMI Amplifier Maximum
Output Current25802001.1V < VCCV< 3.5VCCI Clamp Voltage with
Respect to CCV
UNITSMINTYPMAXCONDITIONSPARAMETER6VSDA= 0.6VSDA Output Low Sink Current-1+1SDA, SCL Input Bias Current2.8SDA, SCL Input High Voltage0.8SDA, SCL Input Low Voltage25802001.1V < VCCI< 3.5VCCV Clamp Voltage with
Respect to CCI
ERROR AMPLIFIERS
TRIP POINTS AND LINEAR CURRENT SOURCES
CURRENT- AND VOLTAGE-SETTING DACs (MAX1647)
SETV, SETI (MAX1648)
LOGIC LEVELS (MAX1647)ChargingCurrent() = 0x000010µA
ChargingCurrent() = 0x001F
MAX1647/MAX1648
Chemistry-Independent Battery Chargers
ELECTRICAL CHARACTERISTICS(VDCIN= 18V, VREF= 4.096V, TA
= -40°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted. Limits over this
temperature range are guaranteed by design.)CS Input Current 5VL < 3.2V, VCS= 12V160185200
MAX1647, SEL = open,
ChargingCurrent( ) = 0x07F0;
MAX1648, VSETI= 1.024V
CS to BATT Full-Scale
Current-Sense Voltage-0.65+0.65
MAX1647, ChargingVoltage( ) = 0x1060,
ChargingVoltage( ) = 0x3130; MAX1648,
VSETV= 3.15V, VSETV= 1.05V
Voltage AccuracyBATT Input Current 5VL < 3.2V, VBATT= 12V614High or lowDLO On-Resistance47High or lowDHI On-Resistance467.5V < VDCIN< 28V, logic inputs = VLDCIN Quiescent Current89DHI Maximum Duty Cycle
kHz200250310Oscillator Frequency5.155.45.657.5V < VDCIN< 28V, no loadVL Output Voltage3.743.94.070µA < ISOURCE< 500µAREF Output Voltage
UNITSMINTYPMAXCONDITIONSPARAMETERmA/V1.4GMV Amplifier Transconductance
mA/V0.2GMI Amplifier Transconductance±130GMV Amplifier Maximum
Output Current±320GMI Amplifier Maximum
Output Current
% of
VREF89.59192.5MAX1647THM THERMISTOR_OR
Over-Range Trip Point
% of
VREF7475.577THM THERMISTOR_COLD
Trip Point1SETV Input Bias Current5SETI Input Bias Current0.8SDA, SCL Input Low Voltage2.8SDA, SCL Input High Voltage-1+1SDA, SCL Input Bias Current
% of
VREF2223.525THM THERMISTOR_HOT
Trip Point
% of
VREF34.56MAX1647THM THERMISTOR_UR
Under-Range Trip Point6VSDA= 0.6VSDA Output Low Sink Current
SUPPLY AND REFERENCE
SWITCHING REGULATOR
ERROR AMPLIFIERS
TRIP POINTS AND LINEAR CURRENT SOURCES
SETV, SETI (MAX1648)
LOGIC LEVELS (MAX1647)
MAX1647/MAX1648
Chemistry-Independent Battery Chargers
TIMING CHARACTERISTICS—MAX1647(TA
= 0°C to +85°C, unless otherwise noted.)
TIMING CHARACTERISTICS—MAX1647(TA
= -40°C to +85°C, unless otherwise noted. Limits over this temperature range are guaranteed by design.)1tDVSCL Falling Edge to SDA Valid,
Master Clocking in Data0tHD:DATSCL Falling Edge to SDA Transition4.7tSU:STAStart-Condition Setup Time4.7tLOW4tHIGHSCL Serial-Clock High Period
SCL Serial-Clock Low Period4tHD:STAStart-Condition Hold Time250tSU:DATSDA Valid to SCL Rising-Edge
Setup Time, Slave Clocking in Data
UNITSMINTYPMAXSYMBOLPARAMETERCONDITIONS
CONDITIONS1tDVSCL Falling Edge to SDA Valid,
Master Clocking in Data0tHD:DATSCL Falling Edge to SDA Transition4.7tSU:STAStart-Condition Setup Time4.7tLOW4tHIGHSCL Serial-Clock High Period
SCL Serial-Clock Low Period4tHD:STAStart-Condition Hold Time250tSU:DATSDA Valid to SCL Rising-Edge
Setup Time, Slave Clocking in Data
UNITSMINTYPMAXSYMBOLPARAMETER
MAX1647/MAX1648
Chemistry-Independent Battery Chargers
__________________________________________Typical Operating Characteristics(Circuit of Figure 3, TA = +25°C, unless otherwise noted.)
MAX1647
BATT LOAD TRANSIENTMAX1647/48-01
ChargingVoltage( ) = 0x2EE0 = 12000mV
ChargingCurrent( ) = 0xFFFF = MAX VALUE
ACDCIN = 18.0V, SEL = OPEN, R1 = 0.1Ω
R2 = 10kΩ, C1 = 68μF, C2 = 0.1μF, C3 = 47nF
L1 = 22μH, VREF = 4.096V
1ms/div
2.4V
12V
VCCI
VCCV
200mV/div
VBATT
1V/div
CCI
CCI
0.9A TO 1.9A TO 0.9A
CCV
CCV
MAX1647
BATT LOAD TRANSIENTMAX1647/48-02
ChargingVoltage( ) = 0x2EE0 = 12000mV
ChargingCurrent( ) = 0x03E8 = 1000mA
ACDCIN = 18.0V, SEL = OPEN, C1 = 68μF,
C2 = 0.1μF, C3 = 47nF, R1 = 0.1Ω
R2 = 10kΩ, L1 = 22μH, VREF = 4.096V
2ms/div
2.3V
12V
VCCV
VCCI
100mV/div
VBATT
5V/div
CCV CCV CCV
CCI
CCI CCI
1.1A TO 0.9A TO 1.1A
VL VOLTAGE vs. LOAD CURRENT
MAX1647/48-03
LOAD CURRENT (mA)
VL (V)
CIRCUIT OF FIGURE 3
VDCIN = 6.6V
INTERNAL REFERENCE VOLTAGE
MAX1647/48-04
LOAD CURRENT (mA)
REF
(V)
16,500
OUTPUT VOLTAGE ERRORMAX1647/48-07
PROGRAMMED VOLTAGE CODE IN DECIMAL
OUTPUT VOLTAGE ERROR (%)
4500850012,500
3mA LOAD
300mA LOAD2500
INPUT AND OUTPUT POWERMAX1647/48-05
CURRENT INTO BATT (mA)
POWER (W)
POWER TO BATT
POWER INTO
CIRCUIT
VDCIN = 28V
VBATT = 12.6V
ChargingCurrent( ) = 0xFFFF
ChargingVoltage( ) = 0xFFFF
MAX1647
OUTPUT V-I CHARACTERISTIC
MAX1647/48-06
LOAD CURRENT (mA)
DROP IN BATT OUTPUT VOLTAGE (%)
VDCIN = 28V, VREF = 4.096V
ChargingVoltage( ) = 0xFFFF
ChargingCurrent( ) = 0xFFFF
BATT NO-LOAD
OUTPUT VOLTAGE = 16.384V
MAX1647/MAX1648
Chemistry-Independent Battery Chargers
______________________________________________________________Pin DescriptionLinear Current-Source Output—1IOUT
Input Voltage for Powering Charger12DCIN
Voltage-Regulation-Loop Compensation Point34CCV
Chip Power Supply. 5.4V linear regulator output from DCIN.23VL
Current-Range Selector. Tying SEL to VL sets a 4A full-scale current. Leaving SEL open
sets a 2A full-scale current. Tying SEL to AGND sets a 1A full-scale current.—6SEL
Battery Voltage Input and Current-Sense Negative Input68BATT
Current-Sense Positive Input57CS
Current-Regulation-Loop Compensation Point45CCI
3.9V Reference Voltage Output or External Reference Input79REF
Current-Regulation-Loop Set Point10—SETI
Voltage-Regulation-Loop Set Point11—SETV
Open-Drain Interrupt Output—11INT
Analog Ground810AGND
Thermistor Sense Voltage Input912THM
Serial Data—14SDA
Power Ground1216PGND
Voltage DAC Output—15DACV
Serial Clock—13SCL
High-Side Power MOSFET Driver Output1418DHI
Power Connection for the High-Side Power MOSFET Driver1620BST
Power Connection for the High-Side Power MOSFET Driver1519LX
Low-Side Power MOSFET Driver Output1317DLO
FUNCTION
PIN
MAX1647MAX1648
NAME
MAX1647/MAX1648
Chemistry-Independent Battery ChargersSTART
CONDITION
MOST SIGNIFICANT
ADDRESS BIT (A6)
CLOCKED INTO SLAVE
A5 CLOCKED
INTO SLAVE
A4 CLOCKED
INTO SLAVE
A3 CLOCKED
INTO SLAVE
tHIGHtLOW
tHD:STA
tSU:STAtSU:DATtHD:DAT
SCL
SDA
tSU:DATtHD:DAT
Figure 1. SMBus Serial Interface Timing—Address
tDV
SLAVE PULLING
SDA LOW
tDV
MOST SIGNIFICANT BIT
OF DATA CLOCKED
INTO MASTER
ACKNOWLEDGE
BIT CLOCKED
INTO MASTER
RW BIT
CLOCKED
INTO SLAVE
SCL
SDA
Figure 2. SMBus Serial Interface Timing—Acknowledge
MAX1647/MAX1648
Chemistry-Independent Battery ChargersAGNDD1
D4*
DC SOURCE
R1B
R1A
REF
THM
CCI
GND
VOUT
IOUT
(NOTE 2)1N.C.
= HIGH-CURRENT TRACES (8A MAX)
NOTE 1: C6, M2, D1, AND C1 GROUNDS MUST CONNECT TO THE SAME RECTANGULAR PAD ON THE LAYOUT.
NOTE 2: C5 MUST BE PLACED WITHIN 0.5cm OF THE MAX1647, WITH TRACES NO LONGER THAN 1cm CONNECTING
VL AND PGND.
*OPTIONAL (SEE NEGATIVE INPUT VOLTAGE PROTECTION SECTION).
VIN
DCIN
MAX1647
SEL
BST
CCV
DACV
DLO
PGND
DHI
(NOTE 1)
SMART BATTERY
STANDARD CONNECTORDC+
BATT
SCL
SDA
INT
HOST AND LOAD
SMBCLOCK
SMBDATA
KINT-
GND
7.5V–28V
MAX874
Figure 3. MAX1647 Typical Application Circuit
MAX1647/MAX1648
Chemistry-Independent Battery Chargers
UNITSQTYDESIGNATION
Table 1a. Component Selection for Figure 3 Circuit (Also Use for Figure 4)
SOURCE/TYPENOTESSprague, 595D476X0020D7T, D case
AVX, TPSE476M020R0150, E case20V, ESR at 250kHz ≤0.4Ω0.1C2, C4, C7, C9
10V, ceramic or low ESRµF1C547C347C1
35V
10VnF22C822C6
NIEC, NSQ03A04, FLAT-PAK (SMC)
NIEC, 30VQ04F, TO-252AA (SMD)
Motorola, MBRS340T3, SMC
Motorola, MBRD340T4, DPAK
Diodes Inc., SK33, SMC
IR, 30BQ040, SMC
3A IDC, 30V Schottky diode, > 0.8W, 1N5821 equivalent
50mA IDC, 40V fast-recovery diode,
1N4150 equivalentD2, D5
Motorola, MMSF5N03HD, SO-8
Motorola, MMDF3N03HD, SO-8
Motorola, MTD20N03HDL, DPAK
IR, IRF7201, SO-8
IR, IRF7303, SO-8
IR, IRF7603, Micro8
Siliconix, Si9410DY, SO-8
Siliconix, Si9936DY, SO-8
Siliconix, Si6954DQ, TSSOP-8
RDS, ON≤0.1Ω, VDSS≥30V, > 0.5W, logic level, N-channel
power MOSFET
Motorola, 2N7002LT1, SOT23
Motorola, MMBF170LT1, SOT23
Diodes Inc., 2N7002, SOT23
Diodes Inc., BS870, SOT23
Zetex, ZVN3306F, SOT23
Central Semiconductor, 2N7002, SOT23
RDS, ON≤10Ω, VDSS≥30V,
logic level, N-channel power
MOSFET, 2N7002 equivalent
D1, D3, D4
VCE, MAX≤-30V, 50mA IC, CONT,
2N3906 equivalentQ1
IRC, CHP1100R100F13, 2512
IRC, LR251201R100F, 2512
Dale, WSL-2512/0.1Ω/±1%, 2512
±1%, 1WmΩ100R1A
Sumida, RCH-110/220M, 10mm x 10mm x 10mm
Coiltronics, UP2-220, 0.541" x 0.345" x 0.231"
Coilcraft, DO3340P-223, 0.510" x 0.370" x 0.450"
Coilcraft, DO5022P-223, 0.730" x 0.600" x 0.280"
±20%, 3A ISAT
Note: size in L x W x HµH22L1
±5%, 1/8WΩ1R1B
±5%, 1/16WkΩ10R2, R4
±1%, 1/16WkΩ10R3
±5%, 1/16WΩ10R5, R7
±5%, 1/8WkΩ10R6
4.3V zener diode,
1N4731 or equivalentD6
_______________Detailed Description
Output CharacteristicsThe MAX1647/MAX1648 contain both a voltage-
regulation loop and a current-regulation loop. Both
loops operate independently of each other. The volt-
age-regulation loop monitors BATT to ensure that its
voltage never exceeds the voltage set point (V0). The
current-regulation loop monitors current delivered to
BATT to ensure that it never exceeds the current-limit
set point (I0). The current-regulation loop is in control
as long as BATT voltage is below V0. When BATT volt-
age reaches V0, the current loop no longer regulates,
and the voltage-regulation loop takes over. Figure 5
shows the V-I characteristic at the BATT pin.
MAX1647/MAX1648
Chemistry-Independent Battery Chargers
Table 1b. Component SuppliersBATTERYC7D3
DC SOURCE
THM
REF
CCIR10
R11
MAX1648
DCIN
CCV
SETV
SETI
BST
DLO
PGND
DHI
BATT
AGND
7.5V–28V
Figure 4. MAX1648 Typical Operating Circuit
847-639-1469847-639-6400Coilcraft
803-626-3123803-946-0690AVX
Central Semiconductor
561-241-9339561-241-7876Coiltronics
FAXPHONEMANUFACTURER512-992-3377512-992-7900IRC
605-665-1627605-668-4131Dale
805-867-2698805-867-2555NIEC
408-970-3950408-988-8000Siliconix
Sprague
847-956-0702847-956-0666Sumida
516-864-7630516-543-7100Zetex
MAX1647/MAX1648
Setting V0 and I0 (MAX1647)Set the MAX1647’s voltage and current-limit set points
through the Intel System Management Bus (SMBus) 2-
wire serial interface. The MAX1647’s logic interprets the
serial-data stream from the SMBus interface to set inter-
nal digital-to-analog converters (DACs) appropriately.
See the MAX1647 Logicsection for more information.
Setting V0 and I0 (MAX1648)Set the MAX1648’s voltage- and current-limit set points
(V0 and I0, respectively) using external resistive dividers.
Figure 6b is the MAX1648 block diagram. V0 equals four
times the voltage on the SETV pin. I0 equals the voltage
on SETI divided by 5.5, divided by R1 (Figure 4).
_____________________Analog SectionThe MAX1647/MAX1648 analog section consists of a
current-mode PWM controller and two transconduc-
tance error amplifiers: one for regulating current and
the other for regulating voltage. The MAX1647 uses
DACs to set the current and voltage level, which are
controlled through the SMBus interface. The MAX1648
eliminates the DACs and controls the error amplifiers
directly from SETI (for current) and SETV (for voltage).
Since separate amplifiers are used for voltage and cur-
rent control, both control loops can be compensated
separately for optimum stability and response in each
state. The following discussion relates to the MAX1647;
however, MAX1648 operation can easily be inferred
from the MAX1647.
Whether the MAX1647 is controlling the voltage or cur-
rent at any time depends on the battery’s state. If the
battery has been discharged, the MAX1647’s output
reaches the current-regulation limit before the voltage
limit, causing the system to regulate current. As the bat-
tery charges, the voltage rises until the voltage limit is
reached, and the charger switches to regulating voltage.
The transition from current to voltage regulation is done
by the charger, and need not be controlled by the host.
Voltage ControlThe internal GMV amplifier controls the MAX1647’s out-
put voltage. The voltage at the amplifier’s noninverting
input amplifier is set by a 10-bit DAC, which is controlled
by a ChargingVoltage( ) command on the SMBus (see
the MAX1647 Logicsection for more information). The
battery voltage is fed to the GMV amplifier through a 4:1
resistive voltage divider. With an external 4.096V refer-
ence, the set voltage ranges between 0 and 16.38V with
16mV resolution.
This poses a challenge for charging four lithium-ion
cells in series: because the lithium-ion battery’s typical
per-cell voltage is 4.2V maximum, 16.8V is required. A
larger reference voltage can be used to circumvent
this. Under this condition, the maximum battery voltage
no longer matches the programmed voltage. The solu-
tion is to use a 4.2V reference and host software.
Contact Maxim’s applications department for more
information.
The GMV amplifier’s output is connected to the CCV
pin, which compensates the voltage-regulation loop.
Typically, a series-resistor/capacitor combination can
be used to form a pole-zero couplet. The pole intro-
duced rolls off the gain starting at low frequencies. The
zero of the couplet provides sufficient AC gain at mid-
frequencies. The output capacitor then rolls off the mid-
frequency gain to below 1, to guarantee stability before
encountering the zero introduced by the output capaci-
tor’s equivalent series resistance (ESR). The GMV
amplifier’s output is internally clamped to between one-
fourth and three-fourths of the voltage at REF.
Current ControlThe internal GMI amplifier and an internal current
source control the battery current while the charger is
regulating current. Since the regulator current’s accura-
cy is not adequate to ensure full 11-bit accuracy, an
internal linear current source is used in conjunction with
the PWM regulator to set the battery current. The cur-
rent-control DAC’s five least significant bits set the
Chemistry-Independent Battery ChargersBATT
VOLTAGE
AVERAGE CURRENT
THROUGH THE RESISTOR
BETWEEN CS AND BATT
V0 = VOLTAGE SET POINT
I0 = CURRENT-LIMIT SET POINT
Figure 5. Output V-I Characteristic
MAX1647/MAX1648
Chemistry-Independent Battery ChargersFigure 6a. MAX1647 Block Diagram
10kΩ10kΩ10kΩ10kΩ8mA4mA2mA1mA
DCIN
IOUT
REF
16mA
REF
THM
AGND
BATT
FROM LOGIC
BLOCK
THERMISTOR_OR
LOGIC
BLOCK
THERMAL
SHUTDOWNTHERMISTOR_COLD
THERMISTOR_HOT
THERM_SHUT
AC_PRESENT
CCV
CCV_LOW
REF
DHI
NOTE: REF/4 TO 3/4 REF
NOTE: APPROX. REF/4 + VTHRESH
TO 3/4 REF + VTHRESH
3/8 REF = ZERO CURRENT
PGND
FROM LOGIC
BLOCKAGND
CCV
CCI
GMI
GMV
BST
DLO
AGND
AGND
MINR
BATT
TO LOGIC BLOCK
FROM LOGIC BLOCK
FROM LOGIC BLOCK
VOLTAGE_INREG
CURRENT_INREGTO LOGIC BLOCK
TO LOGIC BLOCKPOWER_FAIL
6-BIT DAC
REF
AGND
AGND
AGND
REF
DACV
DCIN/4.5
SEL
SCL
SDA
INT
THERMISTOR_UR
100kΩ30kΩ3kΩ500Ω
5.4V LINEAR
REGULATOR
CURRENT-SENSE
LEVEL SHIFT AND
GAIN OF 5.5
CLAMP
10-BIT DAC
LEVEL
SHIFTDRIVER
SUMMING
COMPARATOR
BLOCK
CLAMP
TO REF
(MAX)
INTERNAL 3.9V
REFERENCE
DCIN
DRIVER
