MAX8722AEEG+T

MAX8722AEEG+T Datasheet

MAX8722A

Part	Datasheet
MAX8722AEEG+T	MAX8722AEEG+T (pdf)

Related Parts	Information
MAX8722AEEG+	MAX8722AEEG+

PDF Datasheet Preview
Low-Cost CCFL Backlight Controller MAX8722A The MAX8722A integrated backlight controller is optimized to drive cold-cathode fluorescent lamps CCFLs using a full-bridge resonant inverter architecture. Resonant operation maximizes striking capability and provides near-sinusoidal waveforms over the entire input range to improve CCFL lifetime. The controller operates over a wide input voltage range 4.6V to 28V with high power to light efficiency. The device also includes safety features that effectively protect against many single-point fault conditions including lamp-out and short-circuit faults. The MAX8722A achieves 10:1 dimming range by “chopping” the lamp current on and off using a digital pulsewidth modulation DPWM method. The DPWM frequency can be accurately adjusted with a resistor or synchronized to an external signal. The brightness is controlled by an analog voltage on the CNTL pin. The device directly drives the four external n-channel power MOSFETs of the full-bridge inverter. An internal 5.3V linear regulator powers the MOSFET drivers, the DPWM oscillator, and most of the internal circuitry. The MAX8722A is available in a low-cost, 24-pin QSOP package and operates over a -40°C to +85°C temperature range. Notebook Computer Displays LCD Monitors LCD TVs Synchronized to Resonant Frequency Longer Lamp Life Guaranteed Striking Capability High Power to Light Efficiency Wide Input Voltage Range 4.6V to 28V Input-Voltage Feed-Forward for Excellent Line Rejection Accurate Dimming Control with Analog Interface 10:1 Dimming Range Adjustable Accurate DPWM Frequency with Sync Function Adjustable Lamp Current Rise and Fall Time Secondary Voltage Limit Reduces Transformer Stress Lamp-Out Protection with Adjustable Timeout Secondary Overcurrent Protection with Adjustable Timeout Low-Cost 24-Pin QSOP Package Ordering Information PART TEMP RANGE PIN-PACKAGE MAX8722AEEG -40°C to +85°C 24 QSOP PKG CODE E24-1 Minimal Operating Circuit Pin Configuration TOP VIEW BATT 1 24 GND SHDN 2 ILIM 3 TFLT 4 CNTL 5 MAX8722A 23 VCC 22 VDD 21 PGND 20 GL2 DPWM 6 19 GL1 SYNC 7 18 GH1 FREQ 8 17 LX1 COMP 9 16 BST1 IFB 10 15 BST2 VFB 11 14 LX2 ISEC 12 13 GH2 QSOP BATT BST2 BST1 GH1 ILIM MAX8722A LX1 LX2 FREQ GL1 SHDN CNTL SYNC DPWM COMP TFLT PGND GL2 GH2 VFB ISEC IFB Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at Low-Cost CCFL Backlight Controller MAX8722A ABSOLUTE MAXIMUM RATINGS BATT to +30V BST1, BST2 to GND to +36V BST1 to LX1, BST2 to LX2 to +6V CNTL, FREQ, SYNC, VCC, VDD to GND ...................-0.3V to +6V COMP, DPWM, ILIM, TFLT to GND ............-0.3V to VCC + 0.3V GH1 to LX1 to VBST1 + 0.3V GH2 to LX2 to VBST2 + 0.3V GL1, GL2 to GND to VDD + 0.3V IFB, ISEC, VFB to +6V SHDN to +6V PGND to GND to +0.3V Continuous Power Dissipation TA = +70°C 24-Pin QSOP derate 9.5mW/°C above +70°C ........761.9mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature Storage Temperature Range .............................-65°C to +150°C Lead Temperature soldering, 10s .................................+300°C 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 VBATT = 12V, VCC = VDD, VSHDN = 5.3V, TA = 0°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted. PARAMETER BATT Input Voltage Range BATT Quiescent Current BATT Quiescent Current, Shutdown CONDITIONS VCC = VDD = VBATT VCC = VDD = open VSHDN = VCC, VIFB = 1V VBATT = 28V VBATT = VCC = 5V SHDN = GND MIN TYP MAX UNITS VCC Output Voltage, Normal Operation VCC Output Voltage, Shutdown VCC Undervoltage-Lockout Threshold VCC Undervoltage-Lockout Hysteresis VSHDN = 5.5V, 6V < VBATT < 28V, 0 < ILOAD < 10mA SHDN = GND, no load VCC rising leaving lockout VCC falling entering lockout GH1, GH2, GL1, GL2 OnResistance, High ITEST = 10mA, VCC = VDD = 5.3V GH1, GH2, GL1, GL2 OnResistance, Low ITEST = 10mA, VCC = VDD = 5.3V GH1, GH2, GL1, GL2 Maximum Output Current BST1, BST2 Leakage Current Resonant Frequency Range Minimum Off-Time Maximum Off-Time VBST_ = 12V, VLX_ = 7V Guaranteed by design 340 470 600 Current-Limit Threshold LX1 to PGND, LX2 to PGND Fixed ILIM = VCC 180 200 220 Current-Limit Threshold LX1 to PGND, LX2 to PGND Adjustable VILIM = 0.5V VILIM = 2.0V 100 120

PDF Datasheet Preview

Low-Cost CCFL Backlight Controller

MAX8722A

The MAX8722A integrated backlight controller is optimized to drive cold-cathode fluorescent lamps CCFLs using a full-bridge resonant inverter architecture. Resonant operation maximizes striking capability and provides near-sinusoidal waveforms over the entire input range to improve CCFL lifetime. The controller operates over a wide input voltage range 4.6V to 28V with high power to light efficiency. The device also includes safety features that effectively protect against many single-point fault conditions including lamp-out and short-circuit faults.

The MAX8722A achieves 10:1 dimming range by “chopping” the lamp current on and off using a digital pulsewidth modulation DPWM method. The DPWM frequency can be accurately adjusted with a resistor or synchronized to an external signal. The brightness is controlled by an analog voltage on the CNTL pin. The device directly drives the four external n-channel power MOSFETs of the full-bridge inverter. An internal 5.3V linear regulator powers the MOSFET drivers, the DPWM oscillator, and most of the internal circuitry. The MAX8722A is available in a low-cost, 24-pin QSOP package and operates over a -40°C to +85°C temperature range.

Notebook Computer Displays

LCD Monitors

LCD TVs

Synchronized to Resonant Frequency Longer Lamp Life Guaranteed Striking Capability High Power to Light Efficiency

Wide Input Voltage Range 4.6V to 28V

Input-Voltage Feed-Forward for Excellent Line Rejection

Accurate Dimming Control with Analog Interface
10:1 Dimming Range

Adjustable Accurate DPWM Frequency with Sync Function

Adjustable Lamp Current Rise and Fall Time

Secondary Voltage Limit Reduces Transformer Stress

Lamp-Out Protection with Adjustable Timeout

Secondary Overcurrent Protection with Adjustable Timeout

Low-Cost 24-Pin QSOP Package
Ordering Information

PART

TEMP RANGE PIN-PACKAGE

MAX8722AEEG -40°C to +85°C 24 QSOP

PKG CODE

E24-1

Minimal Operating Circuit

Pin Configuration

TOP VIEW

BATT 1
24 GND

SHDN 2 ILIM 3 TFLT 4 CNTL 5

MAX8722A
23 VCC 22 VDD 21 PGND 20 GL2

DPWM 6
19 GL1

SYNC 7
18 GH1

FREQ 8
17 LX1

COMP 9
16 BST1

IFB 10
15 BST2

VFB 11
14 LX2

ISEC 12
13 GH2

QSOP

BATT

BST2

BST1

GH1 ILIM

MAX8722A LX1 LX2

FREQ GL1

SHDN CNTL SYNC DPWM COMP TFLT

PGND

GL2 GH2 VFB ISEC IFB

Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at

Low-Cost CCFL Backlight Controller

MAX8722A

ABSOLUTE MAXIMUM RATINGS

BATT to +30V BST1, BST2 to GND to +36V BST1 to LX1, BST2 to LX2 to +6V CNTL, FREQ, SYNC, VCC, VDD to GND ...................-0.3V to +6V COMP, DPWM, ILIM, TFLT to GND ............-0.3V to VCC + 0.3V GH1 to LX1 to VBST1 + 0.3V GH2 to LX2 to VBST2 + 0.3V GL1, GL2 to GND to VDD + 0.3V IFB, ISEC, VFB to +6V

SHDN to +6V

PGND to GND to +0.3V

Continuous Power Dissipation TA = +70°C 24-Pin QSOP derate 9.5mW/°C above +70°C ........761.9mW

Operating Temperature Range ...........................-40°C to +85°C Junction Temperature Storage Temperature Range .............................-65°C to +150°C Lead Temperature soldering, 10s .................................+300°C

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 VBATT = 12V, VCC = VDD, VSHDN = 5.3V, TA = 0°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.

PARAMETER BATT Input Voltage Range

BATT Quiescent Current BATT Quiescent Current, Shutdown

CONDITIONS

VCC = VDD = VBATT

VCC = VDD = open

VSHDN = VCC, VIFB = 1V

VBATT = 28V VBATT = VCC = 5V

SHDN = GND

MIN TYP MAX UNITS

VCC Output Voltage, Normal Operation

VCC Output Voltage, Shutdown

VCC Undervoltage-Lockout Threshold

VCC Undervoltage-Lockout Hysteresis

VSHDN = 5.5V, 6V < VBATT < 28V, 0 < ILOAD < 10mA SHDN = GND, no load

VCC rising leaving lockout VCC falling entering lockout

GH1, GH2, GL1, GL2 OnResistance, High

ITEST = 10mA, VCC = VDD = 5.3V

GH1, GH2, GL1, GL2 OnResistance, Low

ITEST = 10mA, VCC = VDD = 5.3V

GH1, GH2, GL1, GL2 Maximum Output Current

BST1, BST2 Leakage Current Resonant Frequency Range Minimum Off-Time Maximum Off-Time

VBST_ = 12V, VLX_ = 7V Guaranteed by design
340 470 600

Current-Limit Threshold LX1 to PGND, LX2 to PGND Fixed

ILIM = VCC
180 200 220

Current-Limit Threshold LX1 to PGND, LX2 to PGND Adjustable

VILIM = 0.5V VILIM = 2.0V
100 120

Notice: we do not provide any warranties that information, datasheets, application notes, circuit diagrams, or software stored on this website are up-to-date or error free. The archived MAX8722AEEG+T Datasheet file may be downloaded here without warranties.

Datasheet ID: MAX8722AEEG+T 647410