MAX17061AETI+-MAX17061AETI+T Fast Delivery |IC PHOENIX CO.,LIMITED

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MAX17061ETI+ ,8-String White LED Driver with SMBus for LCD Panel ApplicationsElectrical Characteristics(Circuit of Figure 1, V = 12V, C = 0.022μF, R = 5.1kΩ, V = V = V = V , R ..
MAX17061ETI+T ,8-String White LED Driver with SMBus for LCD Panel ApplicationsFeatures● Accurate Dimming Control Using SMBus, PWM The MAX17061 is a high-efficiency driver for wh ..
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MAX4525EUB+T ,Low-Voltage, Single-Supply Multiplexer and SwitchGeneral Description ________

MAX17061AETI+-MAX17061AETI+T
8-String White LED Driver with SMBus for LCD Panel Applications
General Description
The MAX17061A is a high-efficiency driver for white
lightemitting diodes (LEDs). It is designed for large liquid-
crystal displays (LCDs) that employ an array of LEDs as
the light source. An internal switch current-mode step-up
controller drives the LED array, which can be configured
for up to eight strings in parallel and 10 LEDs per string.
Each string is terminated with ballast that achieves ±1.5%
current-regulation accuracy between strings, ensuring
even LED brightness. The MAX17061A has a wide input
voltage range from 7.5V to 26V, and provides a fixed
25mA or adjustable 15mA to 30mA full-scale LED current.
The MAX17061A internally generates a DPWM signal for
accurate WLED dimming control. The DPWM frequency
is resistor programmable, while DPWM duty cycle is co
trolled directly from an external PWM signal or through a
control word through the MAX17061A’s SMBus™ inter-
face. This DPWM control provides a dimming range with
8-bit resolution and supports Intel display-power-saving
technology (DPST) to maximize battery life.
The MAX17061A has multiple features to protect the
controller from fault conditions. Separate feedback loops
limit the output voltage under any circumstance, ensuring
safe operation. Once an open string is detected, the string is
disabled while other strings operate normally. The
MAX17061A also features short LED detection. The
shorted strings are also disabled after a 2ms fault
blanking interval. The controller features cycle-by-cycle
current limit to provide stable operation and soft-start
capability. If the MAX17061A is in current-limit condition,
the step-up converter is latched off after an internal timer
expires. A thermal-shutdown circuit provides another level
of protection.
The MAX17061A’s step-up controller features an internal 150mΩ (typ), 45V (max) power MOSFET with local current-
sense amplifier for accurate cycle-by-cycle current limit.
This architecture greatly simplifies the external circuitry
and saves PCB space. Low-feedback voltage at each LED
string 625mV (typ) at 25mA LED current helps reduce
power loss and improve efficiency. The MAX17061A fea-
tures selectable switching frequency (500kHz, 750kHz, or
1MHz), which enables a wide variety of applications that
can trade off component size for operating frequency.
The MAX17061A is available in a thermally enhanced 28-pin, 4mm x 4mm Thin QFN package.
Features●Accurate Dimming Control Using SMBus, PWM
Interface●Dimming Range with 8-Bit Resolution●Adjustable DPWM Frequency with 1.5% Accuracy●Up to Eight Parallel Strings Multiple Series-
Connected LEDs●±1.5% Current Regulation Accuracy Between Strings●Low String Feedback Voltage: 625mV at 25mA LED
Current●Full-Scale LED Current Adjustable from 15mA to
30mA, or Preset 25mA●Open and Short LED Protections●Output Overvoltage Protection●0.15Ω Internal HV Power MOSFET (45V max)●Wide Input-Voltage Range from 4.5V to 26V●500kHz/750kHz/1MHz Selectable Switching Frequency●Small 28-Pin, 4mm x 4mm, Thin QFN package
Applications●Notebook, Subnotebook, and Tablet Computer
Displays●Handy Terminals
SMBus is a trademark of Intel Corp.
FB1
CCV
PGND1, 2
VIN
LX1, 2
FB2
FB3
FB4
FB5
FB6
FB7
FB8D1
VDD
ISET
FSET
VCCVCC
PWMIPWMMAX17061A
VOUT
SCLCLK
SDADATA
OSCN.C.
GND
PWMO
Ordering Information and Pin Description appear at end of
data sheet.
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Simpliied Operating Circuit
EVALUATION KIT AVAILABLE
IN to GND ..............................................................-0.3V to +28VFB_, LX_ to GND ..................................................-0.3V to +45VPGND_ to GND ....................................................-0.3V to +0.3V
VCC, VDD, PWMI, SDA, SCL to GND .....................-0.3V to +6VISET, CCV, PWMO, FSET, OSC, OV to GND ..............................................-0.3V to VCC + 0.3V
Continuous Power Dissipation (TA = +70°C) 28-Pin Thin QFN (derate 16.9mW/°C above +70°C) ...1667mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
(Circuit of Figure 1. VIN = 12V, CCCV = 0.022μF, RCCV = 5.1kΩ, VISET = VOSC = VDD = VCC = 5V, RFSET = 464kΩ, VPWMI = GND,
TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETERCONDITIONSMINTYPMAXUNITS
IN Input Voltage Range7.526V
IN UVLO ThresholdRising edge7.087.27.32VFalling edge6.866.987.1
IN Input CurrentVIN = 26V
MAX17061A is enabled70110
MAX17061A is disabled, TA = +25°C+1+1
VCC Input Voltage4.555.5V
VCC UVLO ThresholdRising edge, typical hysteresis = 10mV4.004.254.45V
VCC Quiescent CurrentMAX17061A is enabled 1.242mA
VCC Shutdown CurrentMAX17061A is disabled10µA
BOOST CONVERTER
LX On-Resistance20mA from LX_ to PGND0.150.3Ω
LX Leakage Current45V on LX_, TA = +25°C1µA
Operating Frequency
VOSC = VCC0.91.01.1MHz
VOSC = open675750825kHz
VOSC = GND450500550
OSC High-Level ThresholdVCC - 0.4V
OSC Midlevel Threshold1.5VCC - 2.0V
OSC Low-Level Threshold0.4V
Minimum Duty CyclePWM mode (Note 1)10%
Maximum Duty Cycle9495.597%
LX Current LimitDuty cycle = 75% (Note 1)1.6A
CONTRL INPUT
SDA, SCL Logic Input High Level2.1
SDA, SCL Logic Input Low Level0.8V
PWMI Logic Input High Level2.1V
PWMI Logic Input Low Level0.8V
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Absolute Maximum Ratings
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.
Electrical Characteristics
(Circuit of Figure 1. VIN = 12V, CCCV = 0.022μF, RCCV = 5.1kΩ, VISET = VOSC = VDD = VCC = 5V, RFSET = 464kΩ, VPWMI = GND,
TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETERCONDITIONSMINTYPMAXUNITS
INPUT LEAKAGE
PWMI Leakage CurrentTA = +25°C-0.3+0.3µA
ISET, FSET Leakage CurrentISET, FSET to VCC, TA = +25°C+1µA
OV Leakage CurrentTA = +25°C-0.1+0.1µA
SDA, SCL Input Bias CurrentTA = +25°C-1+1µA
SDA Output Low Sink CurrentVSDA = 0.4V4mA
OSC Leakage CurrentTA = +25°C3+3µA
LED CURRENT
Full-Scale FB_ Output Current
ISET = VCC24.525.025.5
RISET = 133kΩ28.830.031.2
RISET = 200kΩ19.320.020.7
RISET = 266kΩ14.415.015.6
ISET High-Level ThresholdDefault settingVCC - 0.4V
ISET Output Voltage1.166,1.2361.306V
Current Regulation
Between StringsISET = VCC-1.5+1.5%
Minimum FB_ Regulation
Voltage
IFB_ = 25mA475625910
IFB_ = 30mA5757501100
IFB_ = 20mA380500740
IFB_ = 15mA285375560
Maximum FB_ RippleIFB_ = 20mA (COUT = 1μF, OSC = VCC) (Note 1)120200mVP-P
FB_ On-ResistanceVFB_ = 50mV (includes 10Ω sense resistor)17.528.4Ω
FB_ Leakage Current
VFB_ = 26V, TA = +25°C1
VFB_ = 45V, TA = +25°C2.54
FAULT PROTECTION
OV Threshold VoltageRising edge, typical hysteresis = 60mV1.1661.2361.306V
FB_ Overvoltage Threshold5.25.66.0V
FB_ Undervoltage Threshold130175220mV
Boost Global Fail4884120mV
Thermal-Shutdown Threshold(Note 1)160°C
Overcurrent Fault
Shutdown TimerIPEAK > 3.3A at duty = 0% or 1.8A at duty = 90% (typ)88128168µs
FB_ Overvoltage-Fault Timer1.722.3ms
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Electrical Characteristics (continued)
(Circuit of Figure 1. VIN = 12V, CCCV = 0.022μF, RCCV = 5.1kΩ, VISET = VOSC = VDD = VCC = 5V, RFSET = 464kΩ, VPWMI = GND,
TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
(Circuit of Figure 1, VIN = 12V, CCCV = 0.022μF, RCCV = 5.1kΩ, VISET = VOSC = VDD = VCC, 5V = RFSET = 464kΩ, VPWMI = GND,
TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETERCONDITIONSMINTYPMAXUNITS
IN Input Voltage Range7.526V
IN UVLO ThresholdRising edge7.087.32VFalling edge6.867.1
IN Input CurrentVIN = 26VMAX17061A is enabled110µA
VCC Input Voltage4.55.5V
VCC UVLO ThresholdRising edge, typical hysteresis = 10mV4.004.45V
PARAMETERCONDITIONSMINTYPMAXUNITS
PWM FILTER
PWM Output Impedance204060kΩ
DPWM Oscillator Frequency
RFSET = 464kΩ197200203RFSET = 113kΩ750785820
RFSET = 65kΩ1.2701.3351.400
kHz
RFSET = 42kΩ2
PWMI Input Frequency Range510100kHz
PWMI Full-Range Accuracy5LSB
PWMI Brightness Setting
PWMI duty cycle = 100%98100PWMI duty cycle = 50%485052
PWMI duty cycle = 0%2.62.72.8
SMBus TIMING SPECIFICATION
SMBus FrequencyFSMB10100kHz
Bus Free TimeTBUF4.7µs
START Condition Hold Time from
SCLTHD:STA4µs
START Condition Setup Time
from SCLTSU:STA4.7µs
STOP Condition Setup Time from
SCLTSU:STO4µs
SDA Hold Time from SCLTHD:DAT300µs
SDA Setup Time from SCLTSU:DAT250µs
SCL Low PeriodTLOW4.7µs
SCL High PeriodTHIGH4µs
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Electrical Characteristics (continued)
Electrical Characteristics
(Circuit of Figure 1, VIN = 12V, CCCV = 0.022μF, RCCV = 5.1kΩ, VISET = VOSC = VDD = VCC, 5V = RFSET = 464kΩ, VPWMI = GND,
TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETERCONDITIONSMINTYPMAXUNITS
VCC Shutdown CurrentMAX17061A is disabled10µA
BOOST CONVERTER
LX On-Resistance20mA from LX_ to PGND0.3Ω
Operating Frequency
VOSC = VCC0.891.10MHz
VOSC = open675825
kHz
VOSC = GND450560
OSC High-Level ThresholdVCC - 0.4V
OSC Midlevel Threshold1.5VCC - 2.0V
OSC Low-Level Threshold0.4V
Minimum Duty Cycle94%
LX Current LimitDuty cycle = 75% (Note 1)1.6A
CONTRL INPUT
SDA, SCL Logic Input High Level2.1
SDA, SCL Logic Input Low Level0.8V
PWMI Logic Input High Level2.1V
PWMI Logic Input Low Level0.8V
INPUT LEAKAGE
SDA Output Low Sink CurrentVSDA = 0.4V4mA
LED CURRENT
Full-Scale FB_ Output Current
ISET = VCC24.525.5
RISET = 133kΩ28.631.4
RISET = 200kΩ19.021.0
RISET = 266kΩ14.415.6
ISET High-Level ThresholdDefault settingVCC - 0.4V
ISET Output Voltage1.1661.306V
Current Regulation
Between StringsISET = VCC-1.5+1.5%
Minimum FB_ Regulation
Voltage
IFB_ = 25mA425910
IFB_ = 30mA5751100
IFB_ = 20mA380740
IFB_ = 15mA285560
Maximum FB_ RippleIFB_ = 20mA (COUT = 1μF, OSC = VCC) (Note 1)200mVP-P
FB_ On-ResistanceVFB_ = 50mV (includes 10Ω sense resistor)28.4Ω
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Electrical Characteristics (continued)
Note 1: Specifications are guaranteed by design, not production tested.Note 2: Specifications to -40°C are guaranteed by design, not production tested.
(Circuit of Figure 1, VIN = 12V, CCCV = 0.022μF, RCCV = 5.1kΩ, VISET = VOSC = VDD = VCC, 5V = RFSET = 464kΩ, VPWMI = GND,
TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETERCONDITIONSMINTYPMAXUNITS
FAULT PROTECTION
OV Threshold VoltageRising edge, typical hysteresis = 60mV1.1661.306V
FB_ Overvoltage Threshold5.26.0V
FB_ Undervoltage Threshold130220mV
Boost Global Fail48120mV
Overcurrent FAULT
Shutdown TimerIPEAK > 3.3A at duty = 0% or 1.8A at duty = 90% (typical)88168µs
FB_ Overvoltage Fault Timer1.62.4ms
PWM FILTER
PWM Output Impedance2060kΩ
DPWM Oscillator Frequency
RFSET = 464kΩ197203
RFSET = 113kΩ750820
RFSET = 65kΩ1.271.40kHz
PWMI Input Frequency Range5100kHz
PWMI Full-Range Accuracy5LSB
PWMI Brightness Setting
PWMI duty cycle = 100%98PWMI duty cycle = 50%4852
PWMI duty cycle = 0%2.62.8
SMBus TIMING SPECIFICATION
SMBus FrequencyFSMB10100kHz
Bus Free TimeTBUF4.7µs
START Condition Hold Time from
SCLTHD:STA4µs
START Condition Setup Time
from SCLTSU:STA4.7µs
STOP Condition Setup Time from
SCLTSU:STO4µs
SDA Hold Time from SCLTHD:DAT300µs
SDA Setup Time from SCLTSU:DAT250µs
SCL Low PeriodTLOW4.7µs
SCL High PeriodTHIGH4µs
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Electrical Characteristics (continued)
(Circuit of Figure 1, VIN = 12V, CCCV = 0.022μF, RCCV = 5.1kΩ, VISET = VOSC = VDD = VCC, RFSET = 464kΩ, VPWMI = GND, LEDs = 10 series x 4 parallel strings, TA = +25°C, unless otherwise noted.)
LED CURRENT
vs. SMBus BRIGHTNESS SETTING
MAX17061A toc02
SMBus BRIGHTNESS SETTING
LED CURRENT (mA)
LED CURRENT
vs. PWMI DUTY CYCLE
MAX17061A toc03
PWMI DUTY CYCLE (%)
LED CURRENT (mA)100604020
SMBus = 255
SMBus = 128
LED CURRENT vs. AMBIENT TEMPERATURE
(BRIGHTNESS = 100%)
MAX17061A toc04
AMBIENT TEMPERATURE (°C)
LED CURRENT (mA)804020
LED CURRENT
vs. INPUT VOLTAGE
MAX17061A toc05
LED CURRENT (mA)2014118
SMBus = 0xFF
SMBus = 0x1F
INPUT VOLTAGE (V)
VCC SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX17061A toc06
SUPPLY CURRENT (mA)201510
SMBus = 255
SMBus = 0
VCC SHUTDOWN CURRENT
vs. INPUT VOLTAGE
MAX17061A toc07
SHUTDOWN CURRENT (A)201510
BOOST CONVERTER EFFICIENCY vs.
INPUT VOLTAGE (BRIGHTNESS = 100%)
MAX17061A toc01
INPUT VOLTAGE (V)
BOOST CONVERTER EFFICIENCY (%)201510
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Typical Operating Characteristics
(Circuit of Figure 1, VIN = 12V, CCCV = 0.022μF, RCCV = 5.1kΩ, VISET = VOSC = VDD = VCC, RFSET = 464kΩ, VPWMI = GND, LEDs = 10 series x 4 parallel strings, TA = +25°C, unless otherwise noted.)
STARTUP WAVEFORMS
(BRIGHTNESS = 100%)
MAX17061A toc10
400s/div
VLX
20V/div
1A/div
VOUT
20V/div
VCCV
2V/div
SWITCHING WAVEFORMS
(VIN = 7V, BRIGHTNESS = 100%)
MAX17061A toc08
1s/div
VLX
20V/div
200mA/div
0mA
STARTUP WAVEFORMS
(SMBus = 0x04)
MAX17061A toc11
400s/div
VLX
20V/div
1A/div
VOUT
20V/div
VCCV
2V/div
SWITCHING WAVEFORMS
(VIN = 20V, BRIGHTNESS = 100%)
MAX17061A toc09
1s/div
VLX
20V/div
200mA/div
0mA
LED CURRENT WAVEFORMS
(SMBus = 0x80)
MAX17061A toc12
VFB1
10V/div
500mA/div
ILED
20mA/div
VOUT
20V/div
0mA
0mA
LED CURRENT WAVEFORMS
(SMBus = 0x04)
MAX17061A toc13
VFB1
10V/div
500mA/div
ILED
20mA/div
VOUT
20V/div
0mA
0mA
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Typical Operating Characteristics (continued)
(Circuit of Figure 1, VIN = 12V, CCCV = 0.022μF, RCCV = 5.1kΩ, VISET = VOSC = VDD = VCC, RFSET = 464kΩ, VPWMI = GND, LEDs = 10 series x 4 parallel strings, TA = +25°C, unless otherwise noted.)
LINE TRANSIENT RESPONSE
(VIN = 12V→19V, BRIGHTNESS = 100%)
MAX17061A toc16
100s/div
VOUT
20V/div
1A/div
IFB1
20mA/div
VIN
10V/div
0mA
LED-OPEN FAULT PROTECTION
(BRIGHTNESS = 100%, LED OPEN ON FB1)
MAX17061A toc14
400s/div
VFB1
1V/div
IFB2
20mA/div
IFB2
10V/div
VOUT
20V/div
0mA
LINE TRANSIENT RESPONSE
(VIN = 19V→12V, BRIGHTNESS = 100%)
MAX17061A toc17
100s/div
VOUT
20V/div
1A/div
IFB1
20mA/div
VIN
10V/div
0mA
LED-SHORT FAULT PROTECTION
(BRT = 100%, 2 LEDs SHORT ON FB1)
MAX17061A toc15
1ms/div
VFB1
5V/div
VFB2
10V/div
IFB2
20mA/div
IFB1
20mA/div
0mA
0mA
LED CURRENT BALANCE
vs. INPUT VOLTAGE
MAX17061A toc18
LED CURRENT BALANCE (%)2014118
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Typical Operating Characteristics (continued)
PINNAMEFUNCTIONFB3LED String 3 Cathode Connection. FB3 is the open-drain output of an internal regulator, which controlscurrent through FB3. FB3 can sink up to 30mA. If unused, connect FB3 to VCC.FB4LED String 4 Cathode Connection. FB4 is the open-drain output of an internal regulator, which controlscurrent through FB4. FB4 can sink up to 30mA. If unused, connect FB4 to VCC.GNDAnalog Ground
4, 6, 18N.C.No ConnectionFB5LED String 5 Cathode Connection. FB5 is the open-drain output of an internal regulator, which controls current through FB5. FB5 can sink up to 30mA. If unused, connect FB5 to VCC.FB6LED String 6 Cathode Connection. FB6 is the open-drain output of an internal regulator, which controls current through FB6. FB6 can sink up to 30mA. If unused, connect FB6 to VCC.FB7LED String 7 Cathode Connection. FB7 is the open-drain output of an internal regulator, which controls current through FB7. FB7 can sink up to 30mA. If unused, connect FB7 to VCC.FB8LED String 8 Cathode Connection. FB8 is the open-drain output of an internal regulator, which controls current through FB8. FB8 can sink up to 30mA. If unused, connect FB8 to VCC.OSCOscillator Frequency-Selection Pin. Connect OSC to VCC to set the step-up converter’s oscillator frequency to 1MHz. Connect OSC to GND to set the frequency to 500kHz. Float OSC to set the frequency to 750kHz.PWMI
PWM Signal Input. This PWM signal is used for brightness control in PWM mode or DPST mode. This signal is iltered and its duty cycle is converted into a digital signal to calculate DPWM duty cycle. In PWM
mode, the DPWM duty cycle equals the input PWM duty cycle. In DPST mode, the DPWM duty cycle is the
input PWM duty cycle multiplied by the SMBus brightness command.PWMOFiltered PWM Signal Output. Connect a capacitor between PWMO and GND. The capacitor forms a lowpass ilter with an internal 40kΩ (typ) resistor to ilter the PWM signal into an analog signal whose level
represents the duty-cycle information of the input PWM signal.FSET
DPWM Frequency Adjustment Pin. Connect a resistor from FSET to GND to set the internal DPWM frequency:
where: α = 10.638 γ = 58509
This DPWM signal directly chops WLED current with the calculated duty cycle for brightness control.SDASMBus Serial-Data InputSCLSMBus Serial-Clock InputLX2Boost Regulator Internal MOSFET Drain. Connect the inductor and the Schottky diode to LX2 node. LX2
should always be shorted to LX1 externally.LX1Boost Regulator Internal MOSFET Drain. Connect the inductor and the Schottky diode to LX1 node. LX1
should always be shorted to LX2 externally.PGND2Boost Regulator Power GroundPGND1Boost Regulator Power GroundINSupply Input, 7.5V to 26V. Bypass IN to GND directly at the pin with a 0.1μF or greater ceramic capacitor. When IN voltage is below its UVLO threshold, the MAX17061A turns off the output.
DPWM10fR[]=α×Ω+γ
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Pin Description
Detailed Description
The MAX17061A is a high-efficiency driver for arrays
of white LEDs. It contains a fixed-frequency current-
mode PWM step-up controller, dimming control circuit, SMBus interface, internal power MOSFET, and eight
regulated current sources (see Figure 2). When enabled,
the step-up controller boosts the output voltage to provide
sufficient headroom for the current sources to regulate their
respective string currents. The MAX17061A features select-
able switching frequency (500kHz, 750kHz, or 1MHz),
which allows trade-offs between external component size
and operating efficiency.
WLED brightness is controlled by turning the WLEDs on
and off with a DPWM signal. The DPWM frequency can
be accurately adjusted with a resistor. The brightness of
the LEDs is proportional to the duty cycle of the DPWM
signal, which is controlled externally through either a PWM
or 2-wire SMBus-compatible interface, or both. When both
interfaces are used at the same time, the product of the
PWM duty cycle and SMBus command value is used for
the dimming control. This DPWM control scheme provides
a full dimming range with 8-bit resolution.
The MAX17061A has multiple features to protect the con-
troller from fault conditions. Separate feedback loops limit
the output voltage in all circumstances. The MAX17061A checks each FB_ voltage during the operation. If one or more strings are open, the corresponding FB_ voltages
are pulled below 175mV (typ), and opencircuit fault is
detected. As a result, the respective current sources are
disabled. When one or more LEDs are shorted and the FB_ voltage exceeds 1.1 x VCC, short fault is detected
and the respective current source is disabled. In either
LED open or short conditions, the fault strings are dis-
abled while other strings can still operate normally. The
controller features cycle-by-cycle current limit to provide
stable operation and soft-start protection. In a current-limit condition, the controller shuts down after a 128μs
overcurrent-fault timer expires. A thermal-shutdown circuit
provides another level of protection.
The MAX17061A requires an external 5V supply to provide
PINNAMEFUNCTIONVDDBoost Regulator MOSFET Gate Drive Supply. Bypass VDD to GND with a ceramic capacitor of 1μF or
greater.VCC5V Control Supply Input. VCC provides power to the MAX17061A. Bypass VCC to GND with a ceramic capacitor of 1μF or greater.CCVStep-Up Converter Compensation Pin. Connect a 0.022μF ceramic capacitor and 5.1kΩ resistor from CCVto GND. When the MAX17061A shuts down, CCV is discharged to 0V through an internal 20kΩ resistor.OVOvervoltage Sense. Connect OV to the center tap of a resistive voltage-divider from VOUT to ground. The
detection threshold for voltage limiting at OV is 1.236V (typ).ISET
Full-Scale LED Current Adjustment Pin. The resistance from ISET to GND controls the full-scale current ineach LED string:
ILEDMAX = 20mA x 200kΩ/RISET
The acceptable resistance range is 133kΩ < RISET < 266kΩ, which corresponds to full-scale LED current of
30mA > ILEDMAX > 15mA. Connect ISET to VCC for a default full-scale LED current of 25mA.FB1LED String 1 Cathode Connection. FB1 is the open-drain output of an internal regulator, which controls current through FB1. FB1 can sink up to 30mA. If unused, connect FB1 to VCC.FB2LED String 2 Cathode Connection. FB2 is the open-drain output of an internal regulator, which controls current through FB2. FB2 can sink up to 30mA. If unused, connect FB2 to VCC.EPExposed Backside Pad. Solder to the circuit board ground plane with suficient copper connection to ensure
low thermal resistance. See the PCB Layout Guidelines section.
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Pin Description (continued)
Fixed-Frequency Step-Up Controller
The MAX17061A’s fixed-frequency, current-mode, step-up controller automatically chooses the lowest active FB_
voltage to regulate the output voltage. Specifically, the difference between the lowest FB_ voltage and the
current-source control signal plus an offset (VSAT) is
integrated at the CCV output. The resulting error signal
is compared to the external switch current plus slope
compensation to determine the switch on-time. As the
load changes, the error amplifier sources or sinks current
to the CCV output to deliver the required peak-inductor
current. The slope-compensation signal is added to the
current-sense signal to improve stability at high duty
cycles.
At high input voltages when the on-time is pushed to be lower than the minimum on-time (90ns typ), the boost
converter runs with minimum on-time, boosting the output
voltage higher than the input voltage.
5V Supply VCC and UVLO
The MAX17061A requires an external 5V VCC supply for
internal control voltage.
The MAX17061A includes power-on-reset (POR) and
undervoltage-lockout (UVLO) features. POR resets the
fault latch and sets all the SMBus registers to their
POR values. POR occurs when VCC rises above 2.8V
(typ). The controller is disabled until VCC exceeds the UVLO threshold of 4.25V (typ). Hysteresis on UVLO is
approximately 85mV.
Figure 1. Typical Operating Circuit
FB1
FSETPGND2
PGND1
VIN
7V TO 21V
LX2
FB2
FB3
FB4
FB5
FB6
FB7
FB8
10µH
0.1µF
1µF
1µF
4.7µF
VDD
OSC
GND
VCC
PWMIPWM
ISET
VCC
COUT
LX1
MAX17061A
VOUT
UP TO 45V
220pF
464kΩ
+5V
VCC
0.022µF
5.1kΩ
CCV
SCLCLK
SDADATA
PWMO
61.9kΩ
2µF
2.21MΩ
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications
Figure 2. Control Circuit Block Diagram
IN UVLO
OSCILLATORSLOPE
COMPENSATION
CLOCK
FB OVERVOLTAGE
COMPARATOR
ERROR
COMPARATOR
OUTPUT OVERVOLTAGE
COMPARATOR
VDD
LX1, 2
PGND1, 2
ERROR
AMPLIFIER
CURRENT SOURCE
FB1
GND
FB2
OV FAULT
CONTROL AND
DRIVER LOGIC
CURRENT SENSE
HVCFB6
FB5
FB4
FB3
FB2
LVC
3-LEVEL
COMPARATOR
FB7
FB8
VCC
OSC
REF ADJ
REF
VCC + 0.6V
1.236V
ISET
PWMI
PWMOMUX
0x03"1"
"< = 1"
SCL
SMBus
INTERFACE
8-BIT D/A
VSAT
DPWM SIGNAL GENERATOR
DPWM
SETTING
WLED
ON/OFF
CURRENT SOURCE
SDA
FSET
CCV
VCC
FB3CURRENT SOURCE
FB4CURRENT SOURCE
FB5CURRENT SOURCE
FB6CURRENT SOURCE
FB7CURRENT SOURCE
FB8CURRENT SOURCE
10Ω
MAX17061A
0x020x010x00
MUX
PWM_SEL
PWM_MDDIMMING
BLOCK DIAGRAM
MAX17061A8-String White LED Driver with
SMBus for LCD Panel Applications

Partno	Mfg	Dc	Qty	Available	Descript
MAX17061AETI+ \|MAX17061AETI	MAX	N/a	85	avai	8-String White LED Driver with SMBus for LCD Panel Applications
MAX17061AETI+T \|MAX17061AETIT	MAXIM Pb-free	N/a	799	avai	8-String White LED Driver with SMBus for LCD Panel Applications