MAX8722CEEG+T ,Low-Cost CCFL Backlight ControllerELECTRICAL CHARACTERISTICS(Circuit of Figure 1. V = 12V, V = V , V = 5.4V, T = 0°C to +85°C. Typica ..
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MAX8722CEEG+-MAX8722CEEG+T
Low-Cost CCFL Backlight Controller
General DescriptionThe MAX8722C integrated backlight controller is opti-
mized 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 MAX8722C achieves 10:1 dimming range by “chop-
ping” the lamp current on and off using a digital pulse-
width modulation (DPWM) method. The DPWM frequency
can be accurately adjusted with a resistor or synchro-
nized to an external signal. The brightness is controlled
by an analog voltage on the CNTL pin. The device direct-
ly drives the four external n-channel power MOSFETs of
the full-bridge inverter. An internal 5.4V linear regulator
powers the MOSFET drivers, the DPWM oscillator, and
most of the internal circuitry. The MAX8722C is available
in a low-cost, 24-pin QSOP package and operates over a
-40°C to +85°C temperature range.
ApplicationsNotebook Computer Displays
LCD Monitors
LCD TVs
FeaturesSynchronized to Resonant Frequency
Longer Lamp Life
Guaranteed Striking Capability
High Power to Light EfficiencyWide Input Voltage Range (4.6V to 28V)Input-Voltage Feed-Forward for Excellent Line
RejectionAccurate Dimming Control with Analog Interface10:1 Dimming RangeAdjustable Accurate DPWM Frequency with Sync
FunctionAdjustable Lamp Current Rise and Fall TimeSecondary Voltage Limit Reduces Transformer
StressLamp-Out Protection with Adjustable TimeoutSecondary Overcurrent Protection with
Adjustable TimeoutLow-Cost, 24-Pin QSOP Package
MAX8722C
Low-Cost CCFL Backlight Controller
Ordering Information19-3321; Rev 3; 2/09
EVALUATION KIT
AVAILABLE
PARTTEMP RANGEPIN-PACKAGE PKG
CODE MAX8722CEEG -40°C to +85°C24 QSOP E24-1
MAX8722C
GND
GH2
LX2
BST2
BST1
LX1
GH1
GL1
VDDBATT
IFB
VFB
GL2
ISEC
CNTL
ILIM
FREQ
SYNC
PGND
COMP
VIN
VCC
DPWM
TFLT
VCC
VCC
SHDN
Minimal Operating CircuitGND
VCC
VDD
PGNDTFLT
ILIM
BATT
TOP VIEW
GL2
GL1
GH1
LX1FREQ
SYNC
DPWM
CNTL
BST1
BST2
LX2
GH2ISEC
VFB
IFB
COMP
QSOPMAX8722C
SHDN
Pin Configuration
MAX8722C
Low-Cost CCFL Backlight Controller
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1. VBATT= 12V, VCC= VDD, VSHDN= 5.4V, 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.
BATT to GND..........................................................-0.3V to +30V
BST1, BST2 to GND................................................-0.3V to +36V
BST1 to LX1, BST2 to LX2........................................-0.3V to +6V
CNTL, FREQ, SYNC, VCC, VDDto GND...................-0.3V to +6V
COMP, DPWM, ILIM, TFLT to GND.............-0.3V to (VCC + 0.3V)
GH1 to LX1..............................................-0.3V to (VBST1 + 0.3V)
GH2 to LX2..............................................-0.3V to (VBST2 + 0.3V)
GL1, GL2 to GND.......................................-0.3V to (VDD + 0.3V)
IFB, ISEC, VFB to GND................................................-3V to +6V
SHDNto GND...........................................................-0.3V to +6V
PGND to GND........................................................-0.3V 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......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERCONDITIONSMINTYPMAXUNITS VCC = VDD = VBATT 4.6 5.5 BATT Input Voltage Range VCC = VDD = open 5.5 28.0 V
VBATT = 28V 1 2 BATT Quiescent Current VSHDN = VCC,VIFB = 1V VBATT = VCC = 5.5V 2 mA
BATT Quiescent Current,
Shutdown SHDN = GND 9 26 μA
VCC Output Voltage, Normal
Operation
VSHDN = 5.5V, 6V < VBATT < 28V,
0 < ILOAD< 10mA 5.3 5.40 5.55 V
VCC Output Voltage, Shutdown SHDN = GND, no load 3.5 4.6 5.5 V
VCC rising (leaving lockout) 4.55 VCC Undervoltage-Lockout
Threshold (VUVLO)VCC falling (entering lockout) 3.8 V
VCC Undervoltage-Lockout
Hysteresis 250 mV
GH1, GH2, GL1, GL2 On-
Resistance, High ITEST = 10mA, VCC = VDD = 5.3V 12 24
GH1, GH2, GL1, GL2 On-
Resistance, Low ITEST = 10mA, VCC = VDD = 5.3V 6 12
GH1, GH2, GL1, GL2 Maximum
Output Current 0.3 A
BST1, BST2 Leakage Current VBST_ = 12V, VLX_ = 7V 5 μA
Resonant Frequency Range Guaranteed by design 30 80 kHz
Minimum Off-Time 360 470 620 ns
Maximum Off-Time 23 33 43 μs
Power-On First Pulse First pulse GH2 0.5 0.7 1.0 μs
Current-Limit Threshold
LX1 to PGND, LX2 to PGND
(Fixed)
ILIM = VCC 190 210 230 mV
MAX8722C
Low-Cost CCFL Backlight Controller
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1. VBATT= 12V, VCC= VDD, VSHDN= 5.4V, TA
= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.)
PARAMETERCONDITIONSMINTYPMAXUNITS VILIM = 0.5V 90 120 150 Current-Limit Threshold
LX1 to PGND, LX2 to PGND
(Adjustable) VILIM = 2.0V 380 410 440
Zero-Current Crossing Threshold
LX1 to GND, LX2 to GND -7 0 +7 mV
Current-Limit Leading Edge
Blanking 240 350 460 ns
IFB Input Voltage Range -2 +2 V
IFB Regulation Point 730 780 830 mV
0 < VIFB < 2V -2 +2 IFB Input Bias Current -2V < VIFB < 0 -150 μA
IFB Lamp-Out Threshold 570 600 640 mV
IFB to COMP Transconductance 0.5V < VCOMP < 4V 10 17 25 μS
IFB Soft-Start Disable 1.0 1.1 1.2 V
COMP Output Impedance 5 10 20 M
COMP Discharge Current During
Overvoltage or Overcurrent Fault VIFB = 800mV, VISEC = 2V 1100 μA
COMP Soft-Start Charge Current 1014 20μA
ISEC Overcurrent Threshold 1.15 1.20 1.28 V
ISEC Input Bias Current 0 < VISEC < 2V -0.3 +0.3 μA
VFB Input Bias Current -4V < VVFB < +4V -25 +25 μA
VFB Undervoltage Threshold 340 430 520 mV
VFB Overvoltage Threshold 2.2 2.3 2.4 V
RFREQ = 169k230 260 290
RFREQ = 100k 159 VFB Undervoltage Protection
Timeout
RFREQ = 340k 515
μs
RFREQ = 100k 343
RFREQ = 169k 205 210 215 DPWM Chopping Frequency
RFREQ = 340k 106
Hz
DPWM Input Low Voltage SYNC = VCC, RFREQ = 169k 0.8 V
DPWM Input High Voltage SYNC = VCC, RFREQ = 169k 2.1 V
DPWM Input Hysteresis SYNC = VCC, RFREQ = 169k 100 mV
DPWM Input Bias Current SYNC = VCC, RFREQ = 169k -0.3 +0.3 μA
DPWM Output Low Resistance SYNC = GND, FREQ = VCC 3 k
DPWM Output High Resistance SYNC = VCC, FREQ = VCC 3 k
SYNC Input Low Voltage 0.8 V
SYNC Input High Voltage 2.1 V
SYNC Input Hysteresis 70 mV
SYNC Input Bias Current VSYNC = 2V -0.3 +0.3 μA
MAX8722C
Low-Cost CCFL Backlight Controller
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1. VBATT= 12V, VCC= VDD, VSHDN= 5.4V, TA
= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.)
PARAMETERCONDITIONSMINTYPMAXUNITS SYNC Input Frequency Range 20 100 kHz
CNTL Input Voltage Range 0 2.0 V
CNTL Input Current 0 < VCNTL < VCC -0.1 +0.1 μA
DPWM ADC Resolution Guaranteed monotonic 7 Bits
SHDN Input Low Voltage 0.8 V
SHDN Input High Voltage 2.1 V
SHDN Input Bias Current -1 +1 μA
FREQ Input Regulation Level VCC/2 V
FREQ Input Bias Current FREQ = VCC 230 μA
VISEC < 1.25V and VIFB < 600mV; VTFLT = 2V 0.95 1.00 1.10
VISEC < 1.25V and VIFB > 600mV; VTFLT = 2V -1 TFLT Charge Current
VISEC > 1.25V and VIFB < 600mV; VTFLT = 2V 120
μA
TFLT Trip Threshold 3.95 4.10 4.20 V
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1. VBATT= 12V, VCC= VDD, VSHDN= 5.4V, TA
= -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETERCONDITIONSMINTYPMAXUNITS VCC = VDD = VBATT 4.6 5.5 BATT Input Voltage Range VCC = VDD = open 5.5 28.0 V
VBATT = 28V 2 BATT Quiescent Current VSHDN = VCC, VIFB = 1V VBATT = VCC = 5V 2 mA
BATT Quiescent Current,
Shutdown SHDN = GND 26 μA
VCC Output Voltage, Normal
Operation
VSHDN = 5.5V, 6V < VBATT < 28V
0 < ILOAD< 20mA 5.25 5.50 V
VCC Output Voltage, Shutdown SHDN = GND, no load 3.5 5.5 V
VCC rising (leaving lockout) 4.55 VCC Undervoltage-Lockout
Threshold VCC falling (entering lockout) 3.80 V
GH1, GH2, GL1, GL2
On-Resistance, High ITEST =10mA, VCC = VDD = 5.3V 24
GH1, GH2, GL1, GL2
On-Resistance, Low ITEST =10mA, VCC = VDD = 5.3V 12
BST1, BST2 Leakage Current VBST_ = 12V, VLX_ = 7V 5 μA
Resonant Frequency Range Guaranteed by design 30 80 kHz
Minimum Off-Time 360 620 ns
Maximum Off-Time 23 43 μs
Current-Limit Threshold ILIM = VCC 190 230 mV
MAX8722C
Low-Cost CCFL Backlight Controller
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1. VBATT= 12V, VCC= VDD, VSHDN= 5.4V, TA
= -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETERCONDITIONSMINTYPMAXUNITS VILIM = 0.5V 90 150 Current-Limit Threshold
LX1 - PGND, LX2 - PGND
(Adjustable) VILIM = 2.0V 380 440
Zero-Current Crossing Threshold
LX1 - GND, LX2 - GND -7 +7 mV
Current-Limit Leading Edge
Blanking 240 460 ns
IFB Input Voltage Range -2 +2 V
IFB Regulation Point 720 840 mV
0 < VIFB < 2V -2 +2 IFB Input Bias Current -2V < VIFB < 0 -150 μA
IFB Lamp-Out Threshold 560 650 mV
IFB to COMP Transconductance 0.5V < VCOMP < 4V 10 25 μS
IFB Soft-Start Disable IFB/rising 1 1.2 V
COMP Output Impedance 5 20 M
COMP Soft-Start Charge Current 10 20 mA
ISEC Overcurrent Threshold 1.15 1.28 V
VFB Overvoltage Threshold 2.2 2.4 V
VFB Undervoltage Threshold 340 520 mV
VFB Undervoltage Protection
Timeout RFREQ = 169k 230 290 μs
DPWM Chopping Frequency RFREQ = 169k 205 215 Hz
DPWM Input Low Voltage SYNC = VCC, RFREQ = 169k 0.8 V
DPWM Input High Voltage SYNC = VCC, RFREQ = 169k 2.1 V
DPWM Output Low Resistance SYNC = GND, FREQ = VCC 3.0 k
DPWM Output High Resistance SYNC = VCC, FREQ = VCC 3.0 k
SYNC Input Low Voltage 0.8 V
SYNC Input High Voltage 2.1 V
SYNC Input Frequency Range 20 100 kHz
SHDN Input Low Voltage 0.8 V
SHDN Input High Voltage 2.1 V
TFLT Trip Threshold 3.95 4.20 V
Note 1:Specifications to -40°C are guaranteed by design based on final characterization results.
MAX8722C
Low-Cost CCFL Backlight Controller
Typical Operating Characteristics(Circuit of Figure 1. VBATT= 12V, VCC= VDD,VSHDN= 5.4V, TA= +25°C, unless otherwise noted.)
LOW INPUT-VOLTAGE
OPERATION (VBATT = 8V)MAX8722C toc01
10μs/divAB
A: VIFB, 2V/div
B: VVFB, 2V/div
C: VLX1, 10V/div
D: VLX2, 10V/div
HIGH INPUT-VOLTAGE
OPERATION (VBATT = 20V)MAX8722C toc02
10μs/divAB
A: VIFB, 2V/div
B: VVFB, 2V/div
C: VLX1, 10V/div
D: VLX2, 10V/div
LINE TRANSIENT RESPONSEMAX8722C toc03
20μs/divAB
10V
20V
A: VVFB, 2V/div
B: VIFB, 2V/div
C: VLX1, 10V/div
D: VBATT, 10V/div
LINE TRANSIENT RESPONSEMAX8722C toc04
20μs/divAB
10V
20V
A: VVFB, 2V/div
B: VIFB, 2V/div
C: VLX1, 10V/div
D: VBATT, 10V/div
MINIMUM BRIGHTNESS STARTUP
WAVEFORM (VCNTL = 0)MAX8722C toc05
2ms/divAC
A: VIFB, 2V/div
B: VVFB, 2V/div
C: DPWM, 5V/div
MINIMUM BRIGHTNESS
DPWM OPERATION (VCNTL = 0)MAX8722C toc06
2ms/divABC
A: VIFB, 1V/div
B: VVFB, 2V/div
C: DPWM, 5V/div
MAX8722C
Low-Cost CCFL Backlight Controller
50% BRIGHTNESS DIGITAL
PWM OPERATION (VCNTL = 1V)MAX8722C toc07
2ms/divABC
A: VIFB, 1V/div
B: VVFB, 2V/div
C: DPWM, 5V/div
DPWM SOFT-STARTMAX8722C toc08
40μs/divABC
A: VIFB, 2V/div
B: VVFB, 2V/div
C: DPWM, 5V/div
DPWM SOFT-STOPMAX8722C toc09
40μs/divABC
A: VIFB, 2V/div
B: VVFB, 2V/div
C: DPWM, 5V/div
SWITCHING FREQUENCY
vs. INPUT VOLTAGEMAX8722C toc12
INPUT VOLTAGE (V)
SWITCHING FREQUENCY (kHz)1612
8244ms/div
SECONDARY OVERCURRENT
PROTECTION AND TIMEOUTMAX8722C toc11
A: VISEC, 500mV/div
B: VTFLT, 2V/div
200ms/div
LAMP-OUT VOLTAGE LIMITING
AND TIMEOUTMAX8722C toc10
A: VIFB, 2V/div
B: VVFB, 2V/div
C: VTFLT, 5V/div
Typical Operating Characteristics (continued)(Circuit of Figure 1. VBATT= 12V, VCC= VDD,VSHDN= 5.4V, TA= +25°C, unless otherwise noted.)
MAX8722C
Low-Cost CCFL Backlight ControllerDPWM FREQUENCY vs. RFREQ
MAX8722C toc13
RFREQ (Ω)
DIGITAL PWM FREQUENCY (Hz)
DPWM FREQUENCY
vs. INPUT VOLTAGE
MAX8722C toc14
VIN (V)
DIGITAL PWM FREQUENCY (Hz)
VCNTL = 1.0V
RMS LAMP CURRENT
vs. INPUT VOLTAGEMAX8722C toc15
INPUT VOLTAGE (V)
RMS LAMP CURRENT (mA)1612
NOMINAL CURRENT SET POINT
NORMALIZED BRIGHTNESS
vs. CNTL VOLTAGE
MAX8722C toc16
CNTL VOLTAGE (V)
NORMALIZED BRIGHTNESS (%)
VCC LINE REGULATION
MAX8722C toc17
INPUT VOLTAGE (V)
ACCURACY (%)
VCC LOAD REGULATION
MAX8722C toc18
LOAD CURRENT (mA)
ACCURACY (%)
VCC ACCURACY vs. TEMPERATURE
MAX8722C toc19
TEMPERATURE (°C)
ACCURACY (%)
Typical Operating Characteristics (continued)(Circuit of Figure 1. VBATT= 12V, VCC= VDD,VSHDN= 5.4V, TA= +25°C, unless otherwise noted.)
MAX8722C
Low-Cost CCFL Backlight Controller
PINNAMEFUNCTION 1 BATT Supply Input. BATT is the input to the internal 5.4V linear regulator that powers the device. Bypass BATT
to GND with a 0.1μF ceramic capacitor. SHDN Shutdown Control Input. The device shuts down when SHDN is pulled to GND.
3 ILIM
Primary Current-Limit Adjustment Input. Connect a resistive voltage-divider between VCC and GND to set
the primary current limit. The current-limit threshold is 1/5 of the voltage at ILIM. Connect it to VCC with a
pullup resistor to select the default current-limit threshold of 0.2V.
4 TFLT Fault Timer Adjustment Pin. Connect a capacitor from TFLT to GND to set the timeout periods for open-
lamp and secondary overcurrent faults.
5 CNTL
Brightness Control Input. Varying VCNTL between 0 and 2V varies the DPWM duty cycle (brightness)
between 10% (minimum) and 100% (maximum). The brightness remains at maximum for VCNTL greater
than 2V.
6 DPWM Dual-Function DPWM Signal Pin. The DPWM pin can be used either as the DPWM signal output or as a
low-frequency sync input. See the DPWM Dimming Control and DPWM Frequency Setting sections.
7 SYNC
DPWM High-Frequency Sync Input. The DPWM chopping frequency can be synchronized to an external
high-frequency signal by connecting FREQ to VCC and SYNC to the external signal source. The DPWM
chopping frequency is 1/128 of the frequency of the external signal.
8 FREQ
DPWM Frequency Dual-Mode Adjustment Pin. Connect a resistor from FREQ to GND to set the DPWM
frequency. Connect FREQ to VCC to set DPWM frequency using SYNC.
fDPWM = 210Hz x 169k/RFREQCOMP Transconductance Error-Amplifier Output. A compensation capacitor connected between COMP and GND.
10 IFB
Lamp-Current Feedback Input. The average voltage on IFB is regulated to 0.78V by controlling the on-
time of high-side switches. If VIFB falls below 0.6V for a period longer than the timeout period set by
TFLT, the MAX8722C activates the fault latch.
11 VFB
Transformer Secondary Voltage Feedback Input. A capacitive voltage-divider between the high-voltage
terminal of the CCFL tube and GND sets the maximum average lamp voltage during lamp strike and
open-lamp conditions. When the average voltage on VFB exceeds the internal overvoltage threshold,
the controller turns on an internal current sink discharging the COMP capacitor. The VFB pin is also
used to detect a secondary undervoltage condition. If the peak voltage on VFB is below 430mV
continuously for 260μs (typ) during the DPWM ON period, the MAX8722C shuts down. For the actual
timeout see the VFB Undervoltage Protection Timeout in the Electrical Characteristics table.
12 ISEC
Transformer Secondary Current Feedback Input. A current-sense resistor connected between the low-
voltage end of the transformer secondary and ground sets the maximum secondary current during
faults. When the average voltage on ISEC exceeds the internal overcurrent threshold, the controller turns
on an internal current sink discharging the COMP capacitor.
13 GH2 High-Side MOSFET NH2 Gate-Driver Output
14 LX2
GH2 Gate-Driver Return. LX2 is the input to the current-limit and zero-crossing comparators. The device
senses the voltage across the low-side MOSFET NL2 to detect primary current zero-crossing and
primary overcurrent.
15 BST2 GH2 Gate-Driver Supply Input. Connect a 0.1μF capacitor from LX2 to BST2.
16 BST1 GH1 Gate-Driver Supply Input. Connect a 0.1μF capacitor from LX1 to BST1.
17 LX1
GH1 Gate-Driver Return. LX1 is the input to the current-limit and zero-crossing comparators. The device
senses the voltage across the low-side MOSFET NL1 to detect primary current zero-crossing and
primary overcurrent.
Pin Description
MAX8722C
Low-Cost CCFL Backlight Controller
PINNAMEFUNCTION 18 GH1 High-Side MOSFET NH1 Gate-Driver Output
19 GL1 Low-Side MOSFET NL1 Gate-Driver Output
20 GL2 Low-Side MOSFET NL2 Gate-Driver Output
21 PGND Power Ground. PGND is the return for the GL1 and GL2 gate drivers.
22 VDDLow-Side Gate-Driver Supply Input. Connect VDD to the output of the internal linear regulator (VCC).
Bypass VDD with a 0.1μF capacitor to PGND.
23 VCC5.4V/10mA Internal Linear-Regulator Output. VCC is the supply voltage for the device. Bypass VCC with a
1μF ceramic capacitor to GND.
24 GND Analog Ground. The ground return for VCC, REF, and other analog circuitry. Connect GND to PGND under
the IC at the IC’s backside exposed metal pad.
Pin Description (continued)MAX8722CGND
GH2
LX2
BST2
BST1
LX1
GH1
GL1
VDD
BATT
IFB
VFB
GL2
ISEC
CNTL
ILIM
FREQ
SYNC
PGND
COMP
VIN
VCC
DPWMTFLT
VCC
VCC
SHDN
GND
ON/OFF
BRIGHTNESS
SYNC
DPWM
0.1μF
0.47μF
100kΩ
200kΩ
169kΩ
C10
0.01μFC11
0.22μF
4.7μF
25V
0.47μF
0.1μF
0.1μF
NH1NH2
NL1NL2
1μFCCFL
18pF
3kV
15nFR3
40.2Ω
150Ω
Figure 1. Typical Operating Circuit of the MAX8722C
MAX8722C
Low-Cost CCFL Backlight ControllerMAX8722C
MUXDPWM OSCILLATOR
AND DIMMING
CONTROL LOGIC
LINEAR
REGULATOR
BIAS
SUPPLY
FLTFLT
BST1
GH1
LX1
BST2
GH2
LX2
VDD
GL1
PGND
GL2
ILIM
BATT
VCC
VFB
2.3V
OVERVOLTAGE
COMPARATOR
PWM
COMPARATOR
ERROR
AMPLIFIER
IFB
FREQ
DPWM
SYNC
CNTL
600mV
1.20V
ISEC
OPEN-LAMP
COMPARATOR
SECONDARY
OVERCURRENT
COMPARATOR
GATE-DRIVER
CONTROL
STATE
MACHINE
FAULT
LATCH
RESET
780mV
COMP
OVER-
CURRENT
UVLO
COMPARATOR
VUVLO
PWM CONTROL
LOGIC
RAMP
PRIMARY
OVERCURRENT
AND ZERO-
CROSSING
FAULT DELAYBLOCK
TFLT
UVLO
UVLO
1100μA
OVER-
CURRENT
GND
F.W. RECT
H.W. RECT
SHDN
SHDN
Figure 2. MAX8722C Functional Diagram
